Sales people's commissions tend to be inversely related to customer demand. iPhone demand outstrips supply to incentivizing salespeople to sell iPhones makes no sense.
Agreed about the figures as they can only be inferred. asymco has done some analyses along these lines in the past but I couldn't find one in a hurry (and it might not have been recent). Other indirect measures do not show android is doing better as a "smart" phone (I.e. generator of demand for expensive cellular plans).
But good point about the reverse commissions arrow. I'll have to go check what current commissions are on the iPhones vs previously.