Did it leak when you first got it? Have the plumbing vents been dissasembled, cleaned and properly resealed, what about TV antennas, cable entry points, frigde/stove vents, roof vents etc. Has anything been added to the unit since you purchased it? Remember there is are stringers that run along the length of the trailer that will allow water to travel quite a distance before dripping on your head.
I am not saying you dealer is a bad one, but are the actually removing the old caulk and resealing things or are they just glopping caulking on top of what is already there. That is a favorite trick of peole in any repair business
If a leak started due to mis applied or under applied caulking just sticking some more on top, may stop the leak short term but it WILL start up again shortly, because the joint has been contaminated and is compromised. The only way to assure a good seal is to throughly clean the joint before resealing.
Just a few thoughts and ideas