There will, no doubt, be those who contribute to this thread who will be able to quote cahpter and verse for you. As a lowly line pilot, I have always been instructed (in the UK) that a single engine go-around from at or above DA/MDA follows the MAP; from below DA/MDA the emergency turn procedure. I believe that the logic is tied into the obstacle clearance criteria in that if you are already at DA (say) 200 feet above the runway you already have clearance above any obstacles considered a threat to you losing the engine at V1/Vr.