The VERY first thing you should do is hook up your rig and tow to a very level lot and YOU measure the height of your highest point, probably the top of your front-most AC. There are a number of ways to do this, probably the simplest being to bring a 10-12 foot 2x4 with you to the roof, lay it across the chosen high spot and measure both sides to the ground, add together and divide by two. NOW you know for sure how high the RV really is.
Next, on the way home, stop by your friendly neighborhood CAT scale and weigh the rig again and compare to the weigh sheet from when you weighed it last and see how it compares. Oops, you say you didn't weight it previously? Well then, look up under the rig and see what was added to make up the extra weight they claim. I wouldn't be too concerned about the 350 pounds, but I would be about the height.
Jim and DW 48 years Brenda
2019 F450, ruby red
Harley Road King & sidecar