Basically yes, it is. There's about 3/8" difference in height between crossmember and floor height, and the crossmember sags about 3/8" when substantial weight is applied, giving the 3/4" of warp that the top floor has. The problem I'm facing, at least as I see it; should I attempt to straighten the floor while I have it out? The fiberglass work isn't impressive, and there's some places that could use some attention. Have you ever seen this type of floor out of a boat? If so, was it concave or pretty flat?