Just to follow up.
A week ago (Nov 1st) I restared campaigns, since a new version of the app was released.
I created 3 campaigns.
1. with broad match keywords (ipad/iphone)
2. with exact match keywords NO Search Match (iphone users only)
3. with exact match keywords with Search Match (iphone users only)
Each keyword is now priced at $.60.
No impressions for the past week. Contacting Search Ads support team seems to be useless, since I'm getting the same "template" answer.
So what's next? The only thing I could think of is to adjust the application's Keywords to something different. And then I'll keep my fingers crossed that it will improve "the revelance".
I wish Apple could reply in more technical terms, such as numbers. At this moment, it just feels as unfair competetion.