No problem, thank you so much for responding to me!
Turns out that I was mistaken about the detailed equipment stats; that is still working alongside the overlay, recipes and inventory columns.
As far as I can tell, it seems like Premonition might change the id of the coins/stones. I installed the enlightenment mod on top of the built-in feature of unlimited saves of Premonition and they were considered two different items (with one stack of x99 and a single book that can be reused infinitely). On top of that, the character started with a lucky coin which was singular and not reusable.
When I was in battle I had a stack of an invisible item that had a number of x99, so I assume that was what one of the two was changed to. When I used the item there was no descriptor, item name and no effect, so I don't know if that's helpful at all. Other than that I couldn't find any hint of what the coins/stones had been changed to.
Thank you again!