diff --git a/src/core/rebar/summary.ts b/src/core/rebar/summary.ts
index 60a5200..41e04f5 100644
--- a/src/core/rebar/summary.ts
+++ b/src/core/rebar/summary.ts
@@ -196,7 +196,7 @@ export function rebarSummary(
   const c12Range = side.c12.length ? `${Math.round(side.c12[0].straight)}–${Math.round(side.c12[side.c12.length - 1].straight)}` : '—';
   // Per bar: 2 일자 (straight) and 2 ㄷ (hook body + legs), so 4 bars per row position.
   const sidePieces = (bars: { straight: number }[]) => bars.flatMap((b) => [{ length: b.straight, count: 2 }, { length: hook, count: 2 }]);
-  rows.push({ member: 'coping', name: 'C12', size: 'H25', count: 4 * side.c12.length, length: null, pieces: sidePieces(side.c12), note: `측면, 경사 하면에서 끊김, 일자 ${c12Range} (${2 * side.c12.length}) · ㄷ ${Math.round(hook)} (${2 * side.c12.length})` });
+  rows.push({ member: 'coping', name: 'C12', size: 'H25', count: 4 * side.c12.length, length: null, pieces: sidePieces(side.c12), note: `측면, 경사 하면에서 끊김, 일자 ${c12Range} (${2 * side.c12.length}) · ㄷ ${Math.round(hook)} (${2 * side.c12.length}) · 도면 6단 중 하면 단(EL ${(model.levelBottom + 0.127).toFixed(3)})은 하면 주철근 C7·C8로 계산 (문서 §6.1)` });
   rows.push({ member: 'coping', name: 'C13', size: 'H25', count: 4 * side.c13.length, length: null, pieces: sidePieces(side.c13), note: `측면, 끝면까지, 일자 (${2 * side.c13.length}) · ㄷ ${Math.round(hook)} (${2 * side.c13.length})` });
   // C14 / C15 / C16 are derived from the model (코핑철근.md §7–8); the document's 38 / 11 / 22 and 3852 / 4070 / 4069 are checked in the tests.
   const L14 = model.copingL * 1000;