Option A: Up/Downgrade If a subscription is Up/Downgraded your customer will receive a new invoice according to the new contract.
Option B: Pricing change in a subscription with billing terms “in Advance”
If you make changes on a subscription with billing terms in advance, then the new pricing will appear in the invoice of the next period (after the renewal)
Option C: Pricing change in a subscription with billing terms “at the end of period”
If you make changes on a subscription with billing terms at the end of period, then the new pricing will appear in the invoice of that period (before the renewal)