The "refinance fee" as you have described it is a fee for a subsequent event. Under Â§1026.17(e), it's not required to be disclosed, although you should provide for it in your loan agreement.
An extension of the construction loan term would also be a subsequent event, and the fee not disclosed under Reg Z. Assuming that the extension is accomplished by a modification only extending the loan maturity (or the construction phase of a single-close construction/perm loan), you won't be refinancing, so no Reg Z disclosures here, either.
John S. Burnett
Fighting for Compliance since 1976
Bankers' Threads User #8