The app publishers that are going to be accepted in the network will have full control over what ads that will be displayed. It's their choosing if they which ad they display and where as long their app passes our quality-standards (eg. UI/UX, number of active users, regular updates etc)

I feel like the TinyAds network is more about buying influence and exposure and not a fixed number of impressions (that basically translates to the number of times an ad was loaded and that's it).

Also - I'm not sure why would you think your inventory is doled out since the app publisher accepted your ad and you have the guarantee of the ad being displayed on their app?