diff --git a/AlgebraicDataflowArchitectureModel/models/CustomerOffice.model b/AlgebraicDataflowArchitectureModel/models/CustomerOffice.model
index 83112ba..3a460e2 100644
--- a/AlgebraicDataflowArchitectureModel/models/CustomerOffice.model
+++ b/AlgebraicDataflowArchitectureModel/models/CustomerOffice.model
@@ -1,17 +1,21 @@
 channel C_CustomerAOff_In {
 	out customerA.off(c, setOff(x)) == x
+	out customerA.off(c, e) == c
 }
 
 channel C_CustomerBOff_In {
 	out customerB.off(c, setOff(x)) == x
+	out customerB.off(c, e) == c
 }
 
 channel C_CompanyC1Add_In {
 	out companyC1.add(a, setAdd(y)) == y
+	out companyC1.add(a, e) == a
 }
 
 channel C_CompanyC2Add_In {
 	out companyC2.add(a, setAdd(y)) == y
+	out companyC2.add(a, e) == a
 }
 
 channel CA {