I teach lowering full flap once sure of making the runway.
Which is not particularly clever on a powered approach - you are NEVER 'sure of making the RW' until you cross the threshold, which is far too late to wait to select full flap.
Sensible SOP for
any SEP is:
Roll out of final turn.
Select landing flap, trim.
Adjust IAS to approach speed, trim.
Select touchdown aim point.
Maintain aim point with control column and approach speed with throttle.
So easy - and so intuitive!