The reasoning behind MVP's current way of releasing discs may be financial, in part. How many test Shocks do you want to blow through before you get it right? They might make a few, test them, and if they are coming out close to what they require, they do a full run at those settings.
I don't know how other companies run their test discs but it has to get expensive to keep making discs you never intend to sell if they're not molding up right, even if you regrind the plastic or sell them as X-outs.
MVP Disc Sports