But how much does the report actually tell us?
Not a lot.
We don't know.
We also don't know how they draw the comparison. For example, Angry Birds for iOS is $0.99 but it's free on Android. In this case, do we assume that for every dollar Rovio (maker of Angry Birds) generates in iTunes they generate $0.00 on Android? I really hope not, because that would be absurd.
The bottom line is that we just don't know, because the report did not reveal how the data was collected and from what sources. Instead, we are left taking their word for it.