TL;DRQuantity beyond what the base price already includes, billed at the overage rate.
A plan that includes 10,000 events or 50 seats bills the excess as overage. For volume products with a flat overage band, blocks beyond the included amount bill at the block price in arrears.
For seats, overage quantity is the confirmed seats added after the period started — pending confirmation lots do not count until they are billable.
Where it happens in Sonic
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See it on your contracts
A walkthrough on the agreements and files you actually bill from — not a slide deck.