When a reviewed offer is available, AI Studio billing shows its included standard and advanced usage, plus the separate input and output overage rates, before you confirm a tier change. Input and output share one allowance for each model family.

An already started billing period keeps its saved allowance and rates. If you change tier during that period, the newly accepted usage terms apply from the next period. Existing agreements retain their original terms. If Booking Bible cannot verify a new offer's usage terms, that offer cannot be purchased until it is reviewed.

When a published migration comparison is available, **Billing → Review a new agreement** also shows existing AI Studio allowances, permissions and recorded tier-change requests. Support must reconcile these rights in the migration quote. If an earlier request has no matching scheduled billing change, it needs review before a new agreement can be accepted. Opening the preview does not apply that request or change your current access.