212man,
Caution must be exercised when starting the missed approach before the MAPt - unless it is straight ahead; a MAPt with a turn started too early might put the helicopter into an obstacle area.
For this reason, each procedure must be examined before such choices are made.
You raise an interesting point about the location of the MAPt on the angle between the FAF and the threshhold crossing height. We all make the assumption that an overlay procedure will work without modification but, clearly, the FMS has to be programmed with an algorithm that takes account of that or the procedure has to be hard-wired with a DA at the MAPt.
Are there still procedures out there that have the MAPt after the threshhold?
Jim