Pro-Pack II Ceramic Stone Question

Yes and yes.
A brief story…
Dad and I used to do serious coast to coast road trips.
As a side trip we stopped off at AGRussel in Arkansas. Dad bought me a fairly expensive ultrafine Arkansas stone. Of course I dropped it and broke off about a third of it. I was devistated, and dad got me a replacement. Same batch, same shelf.
The replacement was much rougher. I still have them and I’d guess there is at least 100grit difference.
So inconsistancy in abrasives isn’t new, but it’s interesting there’s so many standards considering the fine industrial uses.