In January my bank originated a closed end HMDA reportable loan on a truck for home improvement purposes, and now in October a change in terms was completed on the original loan extending some more funds to finish the home improvements. How should we report the new transaction?

Modifications aren't reportable. Just for the record, a full-blown refinance of a non-dwelling secured HI loan wouldn't be reportable either.

I believe, however, if additional funds for home improvement were funded with the new request then it would be reportable.

NSF home improvements will always take precedence over a refinance. So if you were to refinance a loan and the borrower was going to use some of the funds for home improvement then you would report the home improvement purpose of the loan.

Raitchjay why would you not report a modification? It seems odd, especially when you advance additional funds. You are now reporting less than was actually advanced to the customer.

Why? Because the GIR says they aren't reportable.

As raitchjay stated, HMDA says:
Modifications and Extensions … are not reportable as refinancings under Regulation C. [HMDA FAQ – Loan Purpose]