The coded part of the approach only starts late in the approach so you are relying on a managed descent most of the way down. Not perfect and not always accurate with the altitude constraints ( I am talking Airbus). I'm not sure how difficult it would be to adjust the databases to make the coded part of the approach start earlier. Before RNP approaches were designed for 33 the problem was always getting too high on the approach as you had to start configuring before HENDO which is 22 miles from the airport. A lot of pilots would think they still had time and space to start throwing gear and flap out.