Chartboost and Corona Ads revenue

I am thinking about integrating chartboost into my app, but I see that Corona takes 5% of the profits. So does this mean that if I have two interstitial ads show up on my app, one from Corona Ads and one from Chartboost, that Corona will take 5% of the profit made by both interstitial ads or just the chartboost one?

Just the Chartboost one.

Just the Chartboost one.