I also felt like the "one time use" comment was odd. I get the point, but I would have figured it was like any other belt. I don't replace a serpentine belt when I change a pulley or replace an alternator. I certainly understand gaskets, filters, o-rings, etc., as being one-time use, but I've never viewed belts that way.
Interesting update for me. I called another dealership in a smaller town about 2 hours away and they are quoting $1,800 - $2,100. She said $2,100 would include all seals and machining the heads. Driving 4 hours to save $1,700 is worth it, IMO.