diff --git a/backend/documents_parser/tests/test_summary_pdf_mapper_chain.py b/backend/documents_parser/tests/test_summary_pdf_mapper_chain.py
index 18e68a60..557ea037 100644
--- a/backend/documents_parser/tests/test_summary_pdf_mapper_chain.py
+++ b/backend/documents_parser/tests/test_summary_pdf_mapper_chain.py
@@ -58,6 +58,7 @@ _SUMMARY_000516_PDF = _FIXTURES / "Summary_000516.pdf"
 _SUMMARY_001479_PDF = _FIXTURES / "Summary_001479.pdf"
 _SUMMARY_000897_PDF = _FIXTURES / "Summary_000897.pdf"
 _SUMMARY_000784_PDF = _FIXTURES / "Summary_000784.pdf"
+_SUMMARY_000899_PDF = _FIXTURES / "Summary_000899.pdf"
 
 # GOV.UK EPB API JSON for cert 001479 — the API-path counterpart of the
 # Summary_001479.pdf fixture. Together they drive the API ≡ Summary
@@ -491,6 +492,34 @@ def test_summary_0330_full_chain_sap_matches_worksheet_pdf_exactly() -> None:
     assert abs(result.sap_score_continuous - worksheet_unrounded_sap) < 1e-4
 
 
+def test_summary_0380_full_chain_sap_matches_worksheet_pdf_exactly() -> None:
+    # Arrange — cert 0380-2471-3250-2596-8761 (Summary_000899.pdf /
+    # dr87-0001-000899.pdf) is the first heat-pump cert under per-cert
+    # Summary-path mapper validation: Mitsubishi PUZ-WM50VHA ASHP
+    # (PCDB index 104568), semi-detached bungalow age D, TFA 60.43 m².
+    # Worksheet PDF "SAP value" line lodges unrounded SAP **88.5104**.
+    # API-path cohort already pinned at the ±0.07 spec-precision floor
+    # (SAP 88.5698, Δ +0.0594); the Summary path becomes the canonical
+    # reference once it closes to 1e-4 — same pattern boilers 001479
+    # and 0330 followed. Diagnostic probe at handover baseline: the
+    # Elmhurst mapper surfaces main_heating_index_number=104568 but
+    # leaves main_heating_category=None, so the cascade misroutes off
+    # the heat-pump path and lands at SAP 33.7920 (Δ -54.7184).
+    pages = _summary_pdf_to_textract_style_pages(_SUMMARY_000899_PDF)
+    site_notes = ElmhurstSiteNotesExtractor(pages).extract()
+    epc = EpcPropertyDataMapper.from_elmhurst_site_notes(site_notes)
+
+    # Act
+    result = calculate_sap_from_inputs(
+        cert_to_inputs(epc, prices=SAP_10_2_SPEC_PRICES)
+    )
+
+    # Assert — 1e-4 pin, no widening, no xfail (project memory
+    # `feedback_zero_error_strict`).
+    worksheet_unrounded_sap = 88.5104
+    assert abs(result.sap_score_continuous - worksheet_unrounded_sap) < 1e-4
+
+
 _API_0330_JSON = (
     Path(__file__).parents[3]
     / "domain/sap10_calculator/rdsap/tests/fixtures/golden"