Initial vs. Monthly Quota in Automatic Translation?

[InfinityBlot (Blot)]

I thought that the initial quota was used before the monthly quota when automatically translating an experience. However, it appears that my experience is using up my monthly quota when I have only used 52% of my initial quota.

Is this an error? Should my experience use 100% of the initial quota before using up the monthly quota?

[InfinityBlot (Blot)]

I also have an experience where the Initial Quota was never used, and only the monthly quota (which has since reset to 0/550k). Is the Monthly Quota used before the Initial Quota?