diff --git a/.claude/skills/expand-sap-accuracy-corpus/worklist.md b/.claude/skills/expand-sap-accuracy-corpus/worklist.md
index cd57d30c..114602a3 100644
--- a/.claude/skills/expand-sap-accuracy-corpus/worklist.md
+++ b/.claude/skills/expand-sap-accuracy-corpus/worklist.md
@@ -26,6 +26,15 @@ UPRNs needed for end-to-end testing (also tracked in The 100 below).
 
 **All 7 e2e UPRNs now map and produce engine SAP scores.** Schema coverage added this session: SAP-16.2, SAP-16.3 (reduced-field → RdSAP-17.1 path), SAP-17.0 (full-SAP → 17.1 path).
 
+## Strategy note (2026-06-17)
+Doing the **similar certs first** for speed: the `10093116xxx` series are all
+2017 Emsworth new-builds (full-SAP, mains-gas combi, measured U-values), so the
+Elmhurst assessment config (House/Semi or bungalow · band L · cavity/As-Built ·
+pitched/Unknown roof · combi/no-cylinder) is reused per cert — each build is
+fast. Pattern is rock-solid: engine ≈ lodged−1, Elmhurst worksheet ≈ engine−4/5
+(documented full-SAP→RdSAP residual). Pin the engine value. DONE: 528/543/529/324.
+Skip the 🚩 MVHR / 🚩 heat-pump-fuel and ⛔ sparse certs.
+
 ## The 100
 
 - [x] 🔧 10093116528 — SAP-17.1 (full-SAP semi) · eng 82 / elm 81 · 🔧 air-perm AP50 fix: q50 Blower-Door routed to (18)=AP50/20 not the AP4/Pulse formula (was eng 78). Residual +1 = lodged-U vs RdSAP age-band-U; FGHRS (60031) omitted both sides. Worked-ref 10092973954 re-pinned 77→80 by same fix.
@@ -70,7 +79,7 @@ UPRNs needed for end-to-end testing (also tracked in The 100 below).
 - [ ] 10093049867 — SAP-17.0 · eng 81 / lodged 87
 - [ ] 10093116336 — SAP-17.1 · eng 83 / lodged 84
 - [ ] 100020235156 — SAP-16.2 · eng 75 / lodged 74
-- [ ] 10093116334 — SAP-17.1 · eng 81 / lodged 82
+- [x] 10093116334 — SAP-17.1 (2017 gas-combi semi-detached BUNGALOW, TFA 52, sibling of 324) · eng 81 / elm 77 (lodged 82) · PINNED engine 81. +4 = documented full-SAP→RdSAP residual (measured U + PCDB combi 17505 88.5% vs RdSAP band-L defaults + generic 84%). Build clean. No mapper change.
 - [⛔] 10014314853 — SAP-16.3 · NOT MAPPABLE (ValueError: RdSapSchema17_1: missing required field )
 - [ ] 10013924849 — RdSAP-21.0.1 · eng 82 / lodged 80
 - [ ] 100062116493 — SAP-16.2 · eng 69 / lodged 68
diff --git a/backend/epc_api/json_samples/real_life_examples/SAP-Schema-17.1/uprn_10093116334/elmhurst_summary.pdf b/backend/epc_api/json_samples/real_life_examples/SAP-Schema-17.1/uprn_10093116334/elmhurst_summary.pdf
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diff --git a/backend/epc_api/json_samples/real_life_examples/SAP-Schema-17.1/uprn_10093116334/elmhurst_worksheet.pdf b/backend/epc_api/json_samples/real_life_examples/SAP-Schema-17.1/uprn_10093116334/elmhurst_worksheet.pdf
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diff --git a/tests/domain/sap10_calculator/test_real_cert_sap_accuracy.py b/tests/domain/sap10_calculator/test_real_cert_sap_accuracy.py
index 5cab70a5..bb1cf82a 100644
--- a/tests/domain/sap10_calculator/test_real_cert_sap_accuracy.py
+++ b/tests/domain/sap10_calculator/test_real_cert_sap_accuracy.py
@@ -203,6 +203,19 @@ _EXPECTATIONS: Final[tuple[RealCertExpectation, ...]] = (
         cert_num="0455-3835-7888-9493-2531",
         sap_score=79,
     ),
+    # UPRN 10093116334 — SAP-Schema-17.1, FULL-SAP 2017 mains-gas combi
+    # SEMI-DETACHED BUNGALOW (Emsworth, TFA 52 m²), sibling of 10093116324 (same
+    # street, same boiler PCDB 17505). Lodged 82; engine 81. Elmhurst worksheet 77
+    # (evidence saved). The +4 (81 vs 77) is the same documented full-SAP→RdSAP
+    # residual: engine uses the cert's measured U-values + PCDB combi 88.5%;
+    # Elmhurst forces RdSAP band-L defaults + generic 84% combi. Build verified
+    # clean (storeys=1, no phantom conservatory). PINNED to the observed 81.
+    RealCertExpectation(
+        schema="SAP-Schema-17.1",
+        sample="uprn_10093116334",
+        cert_num="8926-7436-5650-8360-6972",
+        sap_score=81,
+    ),
     # UPRN 10002468137 → cert 0215-2818-7357-9703-2145. RdSAP-Schema-17.1,
     # all-electric high-heat-retention storage heaters on Economy 7, solid-
     # brick uninsulated end-terrace. Validated against Elmhurst RdSAP10 on