i just found out myself helpless when i changed the ad type in my app from banner to interstitial. But i used the same ad-banner id from admob. though the interstitial are appearing just fine, my ecpm is quite low....
i tried to edit admob adunit type from banner to interstitial for my app but it is disabled under my app setting tab.
so do i have to create a new adunit id for my app and post the new version of my application in the App Store with updated ad unit id?