[ Usage Billing ] What is the monthly cycle for usage billing at shopify's end?

Hi,

We are using usage billing for our app. We bill our customers daily based upon their day’s usage. As you all are aware of when asking permission for usage billing from customer we have to set maximum monthly limit and we can’t charge more than this limit. Which is great for trust. But I need to know what is the monthly cycle for shopify. As in at our end its 1st to last day of month. Logically it should be same at shopify’s end as well. But need some clarification regarding this as it’s not mentioned anywhere in documentation.

The issue is basically suppose if the cycle ends on 25th of each month on shopify’s end , customer already has crossed the maximum limit before 25th so any new usage after 25th till last day should be billable, but on our end we won’t even send the request to billing API because our billing cycle end’s on last day. So we are loosing revenue in this case.

Hope that clears my question. Please share your thoughts.