@Fi I was just looking at this as well out of curiosity and noticed that a few things are different compared to the packs leading them to not be compatible. For example, look at the "Adept" pack. The original pack gave out 2000 credits while the current bronze pack of the same price only gives 500 credits.
As you can see, upgrading this pack to the current next pack of "Silver" would be kind of weird as you wouldn't get any more credits. In fact, in comparing the 2 stores, even the amount of tokens has changed yet the prices have stayed the same:
Old above new below
Seems the entire store amounts have changed completely. I'm not sure if this was addressed in the developer streams but this is probably why the packs are incompatible now.