Are you talking about a rate limit or a quota?
A rate limit (e.g. 100 reuests per second) is subtely different form a uota (10,000 requests over a month), the first will smooth the flow while the second is to enforce billing / governance.
So are you getting odd rate limits (as in you set 50 p/s and you can only get 10 p/s), or are you getting odd quota counts (see the X-Ratelimit headers inthe response)?