The minimum obstacle clearance for NPA is greater than margin and also is based on wider protection areas. With regard to obstacle distance (my generic term) a go around on a NPA DA (no additionals) is safer than GA on an ILS as was always the case - Doc 8168 vol I and II reveal.
This has not been the view of the ICAO Obstacle Clearance Panel (now Instrument Flight Procedures Panel), who are responsible for Doc 8168, whenever someone has suggested that, for CDFA, MDA can equal DA. Also note the safety advisory that EUROCONTROL recently issued:
EUROCONTROL - Safety Alerts Board