Bobby -
another comment worth exactly what you paid for it .... consider that your hull is coated with at least a coat or two of epoxy inside and out - while the deck remains unsealed. This leaves it open to warping and issues of moisture absorbtion.

I had this happen to a set of catamaran hull decks that I was working on - and solved the problem in a two step process that you could consider doing... 1) Coat the underside of the deck and strap it back down to meet your eyeball specifications. 2) After cure, you can coat the top with the exception of where the straps are. My guess is that once you have removed all of the surface area exposed to the environment, you will find much less spring-back. Until it is completely encapsulated, you will always get some amount of dimensional change. Remember that the strips were stapled to a form. Releasing them from the form allows them to move as they try to return to their original shape. Called "spring-back" - it will happen any time you bend wood (and is why you often "over" bend it).

Kind of like applying formica on countertops on BOTH sides to eliminate warp and cup.