Copilot Studio Capacity Pack: Mid-Month Changes and Credit Reset.

If the Copilot Studio credit period is strictly based on the calendar month rather than the subscription billing cycle, how does Microsoft handle a Capacity Pack that is purchased, cancelled, or increased/decreased in the middle of a calendar month?

For example, if our existing Capacity Pack renews on the 17th, but credit usage resets on the 1st, and we add another 25,000-credit Capacity Pack on the 20th, are those additional credits available immediately and valid only until the end of that calendar month, or do they receive a separate monthly allocation through the next billing date?

Also, if credits are consumed before the change and the capacity is later reduced or cancelled during the same month, how is that usage accounted for?

Finally, which exact time zone and timestamp determine the boundary between the last day of one usage month and the 1st of the next?

I’m specifically looking for the actual Microsoft billing/entitlement logic here, rather than a general explanation of the monthly credit model.