An average eCPM is a comfortable number and a poor instruction. The same app can be strong in one country, weak in another, and dependent on a single format for most of the payout.
Split before you optimize
Read revenue by partner, by format and by country on the same week. A partner who looks average overall may be the only bidder showing up for a format you care about. Cutting them on the average would cut that format.
Then change one thing
Move priority, cap a geo, or open a path in the country that is thin. Change one of those, and read the split again. A stack-wide rewrite will not tell you which of the three mattered.
