BCS just removed all my toppers and had the seams restitched with stronger thread, resistant to rot, hopefully. The part of the topper that doesn't roll into the case is exposed to the elements constantly, discolors, and the thread disintegrates there. It can then unwrap in the middle from the cord that holds it to the coach mount, and then belly in the middle due to the looseness.
The labor and seamster cost was pretty steep, and if there's a next time I'll try the job myself. The topper spools are spring loaded, so you have to know what you are doing to be safe.
Joel