1. If you are hit with (Federal) AMT then it does not help[/quote]
??? you mean it would help to pay off the mello roos using a HELOC, right?[/quote]
Precisely. If you are under AMT, you can’t deduct HELOC interest (but you can still deduct mortgage interest). So it might be better to do a cash-out refi instead to raise CLTV up to 80% and then use the cash-out money to pay off Mello Roos.