I've had 3 MH's. And I know lots of folks that have MH's. They flex enough when jacked to either pop out a window or break it. Monaco solved the problem by using three jacks. One up front and two in the back. There's no way to twist the frame with 3 jacks. Other's use 4 jacks and you can twist the frame enough to pop out or break the front window. With 4 jacks you have to be very careful how you operate the jacks. I always used the auto leveling feature and never lost the front window. I did lose it once however when just driving along. The window cutout had been done incorrectly so the glass wasn't sitting in rubber. It hit the fiberglass.