Ando1bar, I can understand teaching a stabilised approach but at 318ft/nm (3deg) in a 172 at 1.57nm at 500ft thats a ROD of 344/min. That seems very shallow, surely it would be better to do the norm and aim for 1 at 500 and go down at 542. That is the essence of a stabilised approach, teach 3deg profile when its required during instrument approach.
I dunno, that's just my thoughts, I dont know the training organisations over all goals but from the outside seems a little arse about.
I think answering the above, with an unquoted explanation from the ops manual, will finally put a rest to this argument. This is now essentially all it has come down to, your final position.
edit/might as well be accurate.