I am thinking about replacing my fascia and soffits at the same time as getting new siding and gutters. The existing fascia, soffits, siding etc are masonite. I was told by a siding company that they would not remove the exsisting fascia they would use it as a subfascia for nailing to with the hardie plank.

There is currently a 1x2 under the drip edge and then a wider board for the fascia beneath it. If they nail a board to the exsisting fascia, won't the water just drip on the new board?

I was told that replacing the exsisting fascia would be difficult because of having to get it under the drip edge without damaging the edge and they would stil need a sub fascia to nail the plank too.

Does all this sound reasonable? Should I worry that the masonite will continue to swell over time and distort the new overlayed hardie plank?