When I was originally speaking about the criteria of FAA vs ICAO, I was referencing the criteria to become RNP and RNP AR certified, not design ctiteria...
Section 1a is the 50' momentary descent...
The 9905 section is not all that clear, in the 9905 approach, Vpa is the glide path..the section shows obstacles in approach and missed approach...
in the diagram, for the approach obstacle, the OCH line would be extended across to SOC', that is your MOC or level section....an MDA if you will, then it is up to the operator to determine the approach minima, using their own calc for momentary descent, but not crossing the MOC...
Here is how you calculate the origin of the missed approach surface, much different that 8260.52... (Ha is the pressure altimeter height loss for the aircraft category!)