Billing for overlay ads in MediaTailor
MediaTailor bills customers based on the number of non-linear ads in the ADS response. This number includes non-linear ads that extend past the break duration. After MediaTailor fills the avail, it bills for the ads it filled.
For prefetch workflows, MediaTailor does not bill for ads when retrieving the prefetch, but rather, when it sees a compatible ad avail in the consumption window for that session.
For additional billing information, see https://aws.amazon.com/mediatailor/pricing/