I'm still on trial with 14d remaining and $2.48 credit left.

On the observability dashboard / Usage from project settings, it shows a total cost of :

Current usage: $0.48

Estimated usage: $0.57

Memory usage: $0.48

Rest is at; $0

Total: $1.53

There is a difference of $0.99 between the consumed credits ($2.52) and the total of usage for the period.

I believe this might be due to the "billing period" (which I expect to start at the 1st of the month thouh).

So my question is: How should I read those costs ? What is the actual billing period and where can I find it ?