We have created a characteristic in CO-PA which can be derived in a number of ways. We have defined four steps in the characteristic derivation strategy, which source the content of the characteristic from different fields in either VBAK or KNB1. The first three steps are made conditional on the source document having particular company codes. The fourth step is a "catch all" which should populate the field if steps 1 to 3 have not already done so. The problem that we have is that in some circumstances the characteristic is being given the value appropriate to step 1 having been executed even when the company code is not what is specified for the step. I have searched OSS, and found several notes which make reference to the table TKEZU, but I am not clear as to exactly how it works. Can anyone help?