The AWS marketplace metering API only accepts 1 usage request per customer/product/hour, subsequent requests are ignored with a status of DUPLICATE_RECORD returned.

There is potential for us to send a duplicate request when a retally occurs. If the retally triggers a usage event to be sent and an hourly tally is already billed for that hour we would not bill for the retally. This card is to investigate if this is possible when retallying so we can address the fix in a follow up card if required.