We were given a good price to layover our spider crack laden fiberglass roof with architectural shingles if we have it done in January. It has only one layer and we understand this is permited. I was warned by a roofer that the first layer could buckle further and cause our new roof to lift up and in a strong wind lose some shingles. Was he just trying to get more money for removing the old layer? Also is it a problem to have the roof reshingled in January or February? Should we wait 'till spring?