diff --git a/Athos/SeeDot/IR/IRBuilderCSF.py b/Athos/SeeDot/IR/IRBuilderCSF.py
index fb0ce8f18c72c89a670d8b3fb700c2a97d880a3e..de0cf2f5f628da8bdb3b6151bd99831949c9cfb6 100644
--- a/Athos/SeeDot/IR/IRBuilderCSF.py
+++ b/Athos/SeeDot/IR/IRBuilderCSF.py
@@ -890,7 +890,7 @@ class IRBuilderCSF(IRBuilderAST):
 			expr2_sf = self.scaleFacMapping[expr_2.idf]
 			if (expr1_sf > self.scaleFac):
 				progExtraBefore = self.addTruncateFunctionCall(node.expr1, "Conv", expr_1, expr1_sf-self.scaleFac)
-				self.scaleFacMapping[expr1.idf] = self.scaleFac
+				self.scaleFacMapping[expr_1.idf] = self.scaleFac
 			if (not inputs_same) and (expr2_sf > self.scaleFac):
 				progExtraBefore = IRUtil.prog_merge(progExtraBefore, self.addTruncateFunctionCall(node.expr2, "Conv", expr_2, expr2_sf-self.scaleFac))
 				self.scaleFacMapping[expr_2.idf] = self.scaleFac