Agree
Sing330,
As IDG said, the 3 deg slope is good to use across the board for all aircrafts and places(even though its a NPA), works a treat, except in certain circumstances where the surveyed approach path is more than 3 deg (usually published due terrain or other reasons)
Commencing the descent 0.3nm prior to the final approach fix, for the 320 is spot on all the time.
With the allowance for TCH, if operating within the US there is no need to factor it in ....so u would enter the published minima into the MDA field when setting it up in the MCDU. When operating outside of the US u would enter MDA+50 as the minima.
Ta