Doing an attic renovation and my contractor installed a new Ameristar furnace and AC up against a hip roof, encased by a kneewall w/pocket door for access to furnace. He installed the AC coil on the back side of the plenum, up against the roof, w/the coil access panel and fittings completely inaccessible. He's saying we'll never need access to the coil or the fittings which I think defies common sense. It seems there are lots of reasons we might need to get to the coil or these fittings - maybe not in the immediate future but some day. He also says he did it this way because to put the coil on the front of the plenum (where it could be easily accessed) would significantly decrease velocity. Does this make any sense?