The MPC wadding did not work very well, anyway. With so much air between the fibers, It did not tend to act like a piston to help push the chute out like most other wadding does. Sorta kinda worked like a re-useable baffle in that sense (but not a very good baffle).
I say most wadding acts like a piston, as I HATE Dog Barf which does NOT help to push the chute out, and lets hot gases blow past it unless you put in a crap-load of way more than sensible. And then if you put in a crap-load it can JAM.
Also, IIRC only the MPC kits had any wadding, not the engine packs. So if your rocket worked well enough to survive a few flights you were out of the MPC wadding and had to use something else anyway.