The term MSRP, in most other industries, stands for Manufacturers Suggested Retail Price. In the RV world, that MSRP number is set by individual dealers. It is based on what the dealer actually pays for the unit, dealer installed options, shipping costs, and dealer mark up (profit margin). Some dealers are a little more greedy than others. Manufacturers have little to nothing to do with RV MSRP's.
You could see twenty trailers, all the same make / model / options, at twenty different dealers, with twenty different MSRP's, and they could vary by as much as 10 - 15 thousand dollars.