something worth mentioning, in the above case he had 12 outs, because he had an inside straight flush draw, but in the 4567 suited example, there were 15 because it was an outside straight flush draw.

and, it doesn't necessarily have to be a straight flush draw to have the same number of outs. you can have the 12 or 15 outs, and still only be drawing to at best a flush or a straight, but have no way of making a straight flush.