If you’ve ever done time with TCC you’ll know that the bane of the out of the box integration possibilities is the employee net-change. This is because it’s a marriage of candidate and user and depending on both of those tables to be clean and ready for this is asking a lot.
I ran across a MOS article that actually made clear about the lookups for those two tables. It’s article Doc ID 1047682.1 and here is the PDF defining the candidate/user update columns in the employee net-change sample.