I'll get this back on track.

If Prevost had to remove some foam to do a repair, then the repair is not complete until they restore the foam.

Charging you extra to replace the foam is BS. Is Prevost so hard up they are starting to look for more ways to vacuum the Lewbucks from our wallets?

If I had to replace the foam that was removed to do the repair I would likely get a small spray foam kit and do it myself. I think there are places that sell small aerosol cans and the two part kits for larger jobs.