411A,
you say: the FAA wants to see a NPA flown to the missed approach point, NOT a miss upon reaching MDA.
In other words: If you reach the MDA before your MAP, you have to fly level at MDA till the MAP before starting the missed approach.
First of all:
purely technically speaking (based on European JAR-OPS); after descending to the MDA on a NPA, you do NOT have to stay level at MDA till the MAP! An MDA is nothing more then a MINIMUM, so there is no rule wharsoever preventing you from already starting to climb up again. However, you are correct on that you have to stay on the appraoch track till the MAP. Only then are you allowed to initiate any turn (if the missed approach calls for that of course...)
Second remark:
I do not know what plane you fly, but it clearly is no airbus with FPA (Flight Path Angle), because then you'd know this discussion of yours is purely theoretical...
FPA allows you to fly a continuous descent NPA, skimming all tops of any intermediate stepdowns (when used correctly), and reaching your MDA at any selected point!
If you use your MAP for this selected point, then your MDA is nothing more then a virtual DH and a go around MUST be flown upon reaching the altitude.
If you work out and use a VDP however, then you may indeed continue your approach by flying level to the MAP, but as the subsequent descent from that MDA at MAP is no longer on your smooth and continuous descent profile, you will easily end up with all kinds of unpleasant audio warnings like: SINK RATE, TOO LOW... TERRAIN etc.. Not really something I'd like to hear on a NPA appoach in poor visibility (only RWY lights in sight, no RWY itself for instance...)
BTW- If Airbus stongly advises against any level flight at MDA on a NPA approach for all these reasons, then why try to be sharper then these highly qualified guys?