As I understand it:
- Max from store = 310 slots (baseline "cap" on shared storage)
- Mordor Ultimate: adds 10 slots to what you already have, and raises your "cap" by 10
- BtS Ultimate, when released: adds 10 slots to what you already have, and raises your "cap" by 10
So, once BtS releases, your cap is either 310, 320 or 330, depending on whether you bought one, both, or neither of those expac Ultimate editions. If one wants to make a distinction between "hard" and "soft" caps, 330 is the most anyone will have for their shared storage, upon BtS release.
Whether you are
at your particular cap, depends on how many slots you bought from the store, in addition to what editions of what expacs you have or have not bought, and whether BtS has released yet.
Is that a reasonable way to state it?
It used to be relatively easy to state: your cap is at 310, unless you bought Mordor Ultimate, in which case it is at 320. But now there's 4 different combinations and 3 different possible caps, as well as the before-BtS-release/after-BtS-release distinction.
I truly don't understand why the shared-storage bump, and the character slot, need to wait until the BtS release. Seems like those are just backend things that could be turned on the moment you make the purchase, like some of the other things in the Ultimate package. But I guess there's technical reasons. I hope it's not just a marketing thing, because the confusion it engenders -- as evident in this thread -- probably
dissuades some folks from buying Ultimate. So that would be a marketing backfire.