Fly26 is absolutely right and demonstrated this in the sim recently the rate at which the trim moves when the flaps are extended is very fast indeed as opposed to when flaps up.
Most 73 drivers probably know this and some don't but next time in the sim ask your instructor to do it and see the effect!
Also reading some of the detail it does contain some of the factors I have observed more and more in the sim especially with new pilots and some old but the tendency to fly with aircraft with trim and treating the trim as the primary flight control.
Instead of using elevator to it best effect the easy thing is just to thumb the trim and keep trimming. You will certainly get a response from the aircraft but not necessarily the one you intended - perhaps!