There are 8-10 square black vents in my current vented attic plus two active vents (both of which I believe do not work.. .we just bought this house but since I intended to foam the attic I did not care whether they worked or not). Is it worth paying to have all of these roof penetrations removed and the area flashed and reshingled, or just leave them as is and foam around and under them? None of the insulation or energy companies that have given me bids have mentioned the existing vents at all. Does it matter much which way I go?