I have the exact same camper and the ceiling around the ac unit had a 1 and 1/2 inch sag in the roof if you put a string from edge corner straight across the ceiling. there is no trusses on each side of the ac unit to hold it up from the weight of it. The camper was still under the warranty but the factory rep looked at it and said it was an acceptable " industry standard ". its not for us up here in snow country , get some good heavy winter snow on it and come spring time it probably would have a 3 inch sag in it so luckily the dealer went at bat for us and fought with keystone and got it fixed and fixed better than factory with added support in the truss structure. Maybe this has happen to yours.