That is what I'm trying to say. You can paint and do carpet and even reroof, but you paint thin vinyl wall board the homses have very little insulation,.. Outlets just pop out of the walls because they're not even in the studs lol. I know, I rented one many many years ago.I have seen many manufactured homes where they are not like 40 year old manufactured homes.
Their finish is very high end. They save money on construction because labor is less expensive than stick built but they are built very close to stick built on quality.
Still I say cost approach in your situation is more important than sales comparision approach.
That is me personally.
I am hoping they at least consider cost basis to some degree. I provided the manufacturer spec sheet, maybe that will help.