Cartel Cargo Unlock Question

I have a question regarding purchasing character personal inventory space unlocks from the Cartel Market:

I have a preferred-status account.

I have some characters with minimum personal inventory (newly created) and I have some with maximum personal inventory (unlocked when I was a subscriber).

I now want to expand some inventory slots on some characters, but preferred status can only do this via CC, not credits.

Question: If I buy the account-wide personal inventory space unlock - does this automatically increase all inventory bays on the account? Or, does it deposit one of those items in your inventory that allows you to "click" and add a slot?

My concern is that if the expansion is automatic, then I am "wasting" some of the unlocks on my characters that already have max inventory.

If it gives each char an item that right-click unlocks, maybe i can use legacy storage to transfer unlocks from max chars to chars that need them?

If anyone can please clarify, I would be thankful. 🙂