diff --git a/fusion_plating/fusion_plating_certificates/models/fp_certificate.py b/fusion_plating/fusion_plating_certificates/models/fp_certificate.py
index e0bd68b4..13e2edf7 100644
--- a/fusion_plating/fusion_plating_certificates/models/fp_certificate.py
+++ b/fusion_plating/fusion_plating_certificates/models/fp_certificate.py
@@ -70,6 +70,18 @@ class FpCertificate(models.Model):
     certified_by_id = fields.Many2one(
         'res.users', string='Certified By', help='Signing authority (e.g. Quality Manager).',
     )
+
+    # ===== Sub 12c — chronological CoC opt-in ===============================
+    body_style = fields.Selection(
+        [
+            ('classic', 'Classic (recipe-order)'),
+            ('chronological', 'Chronological (chain-of-custody)'),
+        ],
+        string='CoC Body Style', default='classic',
+        help='Chronological walks fp.job.step.move records in time order '
+             'with measurement sub-tables per move, matching Steelhead\'s '
+             'CoC PDF layout. Classic uses the existing recipe-order body.',
+    )
     issue_date = fields.Date(string='Issue Date', default=fields.Date.today, tracking=True)
     attachment_id = fields.Many2one('ir.attachment', string='Certificate PDF')
     thickness_reading_ids = fields.One2many(
diff --git a/fusion_plating/fusion_plating_certificates/views/fp_certificate_views.xml b/fusion_plating/fusion_plating_certificates/views/fp_certificate_views.xml
index 02d12422..7cac6fc8 100644
--- a/fusion_plating/fusion_plating_certificates/views/fp_certificate_views.xml
+++ b/fusion_plating/fusion_plating_certificates/views/fp_certificate_views.xml
@@ -93,6 +93,7 @@
                         <group>
                             <field name="issued_by_id"/>
                             <field name="certified_by_id"/>
+                            <field name="body_style"/>
                         </group>
                         <group>
                             <field name="reading_count" readonly="1"/>
diff --git a/fusion_plating/fusion_plating_reports/report/report_coc.xml b/fusion_plating/fusion_plating_reports/report/report_coc.xml
index 94eaa42b..41ac16b4 100644
--- a/fusion_plating/fusion_plating_reports/report/report_coc.xml
+++ b/fusion_plating/fusion_plating_reports/report/report_coc.xml
@@ -307,7 +307,8 @@
                 <t t-call="web.external_layout">
                     <t t-set="LANG" t-value="'en'"/>
                     <div class="page">
-                        <t t-call="fusion_plating_reports.coc_body"/>
+                        <!-- Sub 12c — router picks chronological vs classic body -->
+                        <t t-call="fusion_plating_reports.coc_body_router"/>
                     </div>
                 </t>
             </t>
@@ -324,7 +325,8 @@
                 <t t-call="web.external_layout">
                     <t t-set="LANG" t-value="'fr'"/>
                     <div class="page">
-                        <t t-call="fusion_plating_reports.coc_body"/>
+                        <!-- Sub 12c — router picks chronological vs classic body -->
+                        <t t-call="fusion_plating_reports.coc_body_router"/>
                     </div>
                 </t>
             </t>
diff --git a/fusion_plating/fusion_plating_reports/report/report_coc_chronological.xml b/fusion_plating/fusion_plating_reports/report/report_coc_chronological.xml
new file mode 100644
index 00000000..bc40666a
--- /dev/null
+++ b/fusion_plating/fusion_plating_reports/report/report_coc_chronological.xml
@@ -0,0 +1,211 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<!--
+    Copyright 2026 Nexa Systems Inc.
+    License OPL-1 (Odoo Proprietary License v1.0)
+    Part of the Fusion Plating product family.
+
+    Sub 12c — Chronological CoC body.
+    Walks fp.job.step.move records in time order (chain-of-custody),
+    rendering each transition as a heading ("Step Name (Tank Code)")
+    with a "Moved By / Time" meta line + a 5-column measurement
+    sub-table when the destination step has captured input values.
+    Mirrors Steelhead's CoC PDF layout (screens 19-24).
+
+    Wired via fp.certificate.body_style = 'chronological' through the
+    coc_body_router template.
+-->
+<odoo>
+
+    <template id="coc_body_chronological">
+        <!-- Resolve the linked job. fp.certificate has x_fc_job_id (Sub 11+). -->
+        <t t-set="job" t-value="('x_fc_job_id' in doc._fields and doc.x_fc_job_id) or False"/>
+        <t t-set="moves" t-value="(job and 'move_ids' in job._fields and job.move_ids.sorted('move_datetime')) or []"/>
+
+        <style>
+            .fp-coc-chrono { font-family: Arial, sans-serif; font-size: 9pt; color: #000; padding-top: 8mm; }
+            .fp-coc-chrono h1 { text-align: center; font-size: 18pt; margin: 0 0 6px 0; font-weight: bold; }
+            .fp-coc-chrono h3 { font-size: 11pt; margin: 8px 0 2px 0; font-weight: bold; }
+            .fp-coc-chrono .fp-chrono-meta { font-size: 8.5pt; color: #444; margin-bottom: 4px; }
+            .fp-coc-chrono table.bordered,
+            .fp-coc-chrono table.bordered th,
+            .fp-coc-chrono table.bordered td { border: 1px solid #000; border-collapse: collapse; }
+            .fp-coc-chrono table.bordered { width: 100%; margin-bottom: 8px; }
+            .fp-coc-chrono table.bordered th { background: #ededed; padding: 4px 6px; font-size: 8.5pt; text-align: center; }
+            .fp-coc-chrono table.bordered td { padding: 4px 6px; vertical-align: top; font-size: 8.5pt; }
+            .fp-coc-chrono .text-center { text-align: center; }
+            .fp-coc-chrono hr.heavy { border: 0; border-top: 2px solid #000; margin: 8px 0; }
+        </style>
+
+        <div class="fp-coc-chrono">
+
+            <h1>Certificate of Conformance</h1>
+
+            <!-- Job header (compact) -->
+            <table class="bordered">
+                <tr>
+                    <th style="width: 18%;">Part Number</th>
+                    <th style="width: 28%;">Description</th>
+                    <th style="width: 8%;">Quantity</th>
+                    <th style="width: 8%;">Work Order</th>
+                    <th style="width: 14%;">PO Number</th>
+                    <th style="width: 14%;">Packing List No</th>
+                    <th style="width: 10%;">Date</th>
+                </tr>
+                <tr>
+                    <td>
+                        <t t-if="job and 'part_catalog_id' in job._fields and job.part_catalog_id">
+                            <span t-esc="job.part_catalog_id.part_number or job.product_id.default_code or '—'"/>
+                        </t>
+                        <t t-else="">
+                            <span t-esc="(job and job.product_id and job.product_id.default_code) or '—'"/>
+                        </t>
+                    </td>
+                    <td>
+                        <t t-if="job and 'part_catalog_id' in job._fields and job.part_catalog_id">
+                            <span t-esc="job.part_catalog_id.name or job.product_id.name or '—'"/>
+                        </t>
+                        <t t-else="">
+                            <span t-esc="(job and job.product_id and job.product_id.name) or '—'"/>
+                        </t>
+                    </td>
+                    <td class="text-center">
+                        <span t-esc="(job and job.qty) or ''"/>
+                    </td>
+                    <td class="text-center">
+                        <span t-esc="(job and job.name) or '—'"/>
+                    </td>
+                    <td>
+                        <span t-esc="(job and job.sale_order_id and job.sale_order_id.client_order_ref) or '—'"/>
+                    </td>
+                    <td/>
+                    <td>
+                        <span t-esc="(doc.create_date and doc.create_date.strftime('%Y-%m-%d')) or ''"/>
+                    </td>
+                </tr>
+            </table>
+
+            <h3 style="margin-top: 6px;">Specification(s):
+                <span style="font-weight: normal;"
+                      t-esc="(job and job.recipe_id and job.recipe_id.name) or '—'"/>
+            </h3>
+
+            <hr class="heavy"/>
+
+            <!-- Chain-of-custody walk -->
+            <t t-foreach="moves" t-as="mv">
+                <t t-set="dest" t-value="mv.to_step_id"/>
+                <t t-set="tank_code" t-value="(mv.to_tank_id and mv.to_tank_id.code) or (dest and dest.tank_id and dest.tank_id.code) or ''"/>
+                <t t-set="captured" t-value="(dest and dest.input_ids.filtered(lambda i: (i.kind or 'step_input') == 'step_input').sorted('sequence')) or []"/>
+
+                <h3>
+                    <span t-esc="(dest and dest.name) or '—'"/>
+                    <t t-if="tank_code"> (<span t-esc="tank_code"/>)</t>
+                </h3>
+                <div class="fp-chrono-meta">
+                    <strong>Moved By:</strong> <span t-esc="mv.moved_by_user_id.name"/>
+                    <span> · </span>
+                    <strong>Time:</strong>
+                    <span t-esc="mv.move_datetime and mv.move_datetime.strftime('%b %d, %Y %I:%M:%S %p') or ''"/>
+                    <t t-if="mv.qty_moved">
+                        <span> · </span>
+                        <strong>Qty:</strong> <span t-esc="mv.qty_moved"/>
+                    </t>
+                </div>
+
+                <!-- Measurement sub-table — only when the destination step has step_input prompts -->
+                <t t-if="captured">
+                    <table class="bordered">
+                        <thead>
+                            <tr>
+                                <th style="width: 24%;">Name</th>
+                                <th style="width: 30%;">Description</th>
+                                <th style="width: 14%;">Target</th>
+                                <th style="width: 18%;">Actual</th>
+                                <th style="width: 14%;">Recorded By</th>
+                            </tr>
+                        </thead>
+                        <tbody>
+                            <t t-foreach="captured" t-as="inp">
+                                <tr>
+                                    <td><span t-esc="inp.name"/></td>
+                                    <td>
+                                        <t t-if="inp.hint">
+                                            <span t-esc="inp.hint"/>
+                                        </t>
+                                    </td>
+                                    <td class="text-center">
+                                        <t t-if="'target_min' in inp._fields and inp.target_min and inp.target_max">
+                                            <span t-esc="inp.target_min"/>–<span t-esc="inp.target_max"/>
+                                            <t t-if="'target_unit' in inp._fields and inp.target_unit">
+                                                <span> </span><span t-esc="inp.target_unit"/>
+                                            </t>
+                                        </t>
+                                        <t t-elif="'target_unit' in inp._fields and inp.target_unit">
+                                            <span t-esc="inp.target_unit"/>
+                                        </t>
+                                    </td>
+                                    <td/>
+                                    <td>
+                                        <span t-esc="(mv.moved_by_user_id and mv.moved_by_user_id.name) or ''"/>
+                                    </td>
+                                </tr>
+                            </t>
+                        </tbody>
+                    </table>
+                </t>
+            </t>
+
+            <hr class="heavy"/>
+
+            <!-- Sign-off block (re-uses owner_user_id signature pattern from coc_body) -->
+            <t t-set="owner_sig" t-value="False"/>
+            <t t-if="company.x_fc_owner_user_id">
+                <t t-set="_emp" t-value="company.x_fc_owner_user_id.employee_ids[:1]"/>
+                <t t-if="_emp and 'signature' in _emp._fields">
+                    <t t-set="owner_sig" t-value="_emp['signature']"/>
+                </t>
+            </t>
+            <t t-set="signature_img" t-value="company.x_fc_coc_signature_override or owner_sig"/>
+            <t t-set="signer_name" t-value="(doc.certified_by_id and doc.certified_by_id.name) or (company.x_fc_owner_user_id and company.x_fc_owner_user_id.name) or ''"/>
+
+            <table class="bordered">
+                <tr>
+                    <td style="width: 50%; vertical-align: top;">
+                        <strong>Certified By:</strong><br/>
+                        <t t-if="signature_img">
+                            <img t-att-src="'data:image/png;base64,%s' % signature_img.decode()"
+                                 style="max-height: 22mm; max-width: 70mm;"/>
+                        </t><br/>
+                        <strong>Name:</strong> <span t-esc="signer_name"/>
+                    </td>
+                    <td style="width: 50%; vertical-align: top;">
+                        <strong>Certification Statement:</strong>
+                        <span style="font-size: 8.5pt;">
+                            Ref. WO# <span t-esc="(job and job.name) or ''"/>
+                        </span>
+                        <p style="font-size: 8pt; margin-top: 4px;">
+                            We certify that the parts listed above have been processed
+                            in accordance with the specifications referenced and that
+                            all required tests have been performed. Records on file at
+                            our facility per AS9100 / ISO 9001 retention policy.
+                        </p>
+                    </td>
+                </tr>
+            </table>
+        </div>
+    </template>
+
+    <!-- ============================================================== -->
+    <!-- Router — picks chronological vs classic body                    -->
+    <!-- Wired into the existing CoC actions in report_coc.xml.          -->
+    <!-- ============================================================== -->
+    <template id="coc_body_router">
+        <t t-if="doc.body_style == 'chronological' and 'x_fc_job_id' in doc._fields and doc.x_fc_job_id">
+            <t t-call="fusion_plating_reports.coc_body_chronological"/>
+        </t>
+        <t t-else="">
+            <t t-call="fusion_plating_reports.coc_body"/>
+        </t>
+    </template>
+
+</odoo>