Thanks for confirming the A/T modes, in particular the RETARD at 27' RA with A/T engaged on a manual or autopilot flown approach.
As far as i'm concerened there is nothing wrong with the design philosophy, this was a lack of basic flying combined with too much faith in the automatics!
Setting aside the obvious lack of basic airmanship for a moment.
The design problem I see is having a 'convenience' function - retarding the throttles at 27' RA - lead to a situation were the throttles are brought to idle at 2000' without input from the crew because of a faulty RA#1. We don't really need that function on a manual or autopilot flown approach to Cat 1 minimums, so why is it there with the potential to trip up an inattentive crew?