A weird odds situation - a case for drawing to big overcards

[James282]

I am not sure as to the utility of this - but it intrigues me a little. When calculating odds on later streets in hands, we typically this basic formula:

Let's say I have AK. I raise in the CO and only the BB calls. The flop is a rainbow 458. The BB check-raises me and at this point I know he must have a pair(to simplify the calculation). The pot is kinda small, so I peel the turn. The turn is a seemingly innocuous queen. He bets again and since I think he won't defend Q8 or worse I know I will often have 6 live outs here. So I figure, 6 of the 46 cards left are an ace or a king that will likely improve me to the best hand.

But this seems to omit much of the information that we have. The hand is heads up - which means that 1 of the cards in all of my opponents was not an ace or a king - assuming nobody folds AK, AA, or KK in situations like this(which is a pretty safe assumption, especially at higher limits). So aren't my odds more like 6/37? Aren't there many more situations we could conceivably think about this way?
-James