The problem as I see it is that many European operators have been flying stabilised approaches for years and have been following the PANS-OPS guidance that has been there since Pontius: The DA/DH is based upon the OCA/H with an additional margin 'based upon operational consideration of
– category of operation
– ground/airborne equipment characteristics
– aircraft performance
– meteorological conditions
– aerodrome characteristics
– terrain profile/radio altimeter
– pressure error/pressure altimeter
- etc.
And they usually came up with a figure in the region of 50ft - although some decided that no add-on was necessary.
EU-Ops tried to capture all this in the CDFA and RVR sections without much success. EASA is in the process of rewriting EU Ops as IR Ops but it could be some time before that sees the light of day. In the meantime, States have committed themselves to publishing RNP APCHs to LNAV/VNAV minima for all instrument runway ends by 2016 (or thereabouts). If you fly to LNAV/VNAV minima the problem goes away.
I have heard that at least one major European State has taken a similar view to the FAA - if the visual segment has been appropriately assessed for obstacles (it has to be done for RNP APCH to LNAV/VNAV) then MDA=DA. But then if there is an LNAV/VNAV approach published, why fly CDFA on a conventional NPA?