We have a commercial entity borrower that requested a new $200M working capital LOC that terminated 2 existing $100M lines of credit. In addition to a UCC on ABA for the new line, we are also taking a 4th on the personal residence of the owner. IF either of the two prior lines being paid off were collateralized by a mortgage on the personal residence, we have a refinance, and the new line is reportable, even though the purpose is working capital. Is my thinking correct?

If the borrower is the same, then yes, and I don't think it matters if it's the same collateral. If either of the lines being paid off was secured by a dwelling and that line was in the name of your current borrower, then it is a refi. Sometimes borrower is not the same in the commercial world though.