Have you verified that your API is functioning properly? The FAQ says that a number of stats have to be submitted before it will show up on your revenue page (including the %), so maybe you just need to wait.
Why is my game not getting the 10% ad revenue bonus?
The system looks for a small number (50) of successful statistic submissions to confirm that the API is consistently working well. […] Your revenue will show as $0.00 and 0% revenue share until we update it, even if the report shows gameplays.