What we need to avoid is the widespread and very dangerous notion that you do things one way during training and a completely different way as soon as you get the PPL
Who said that and in what context.
Might be missing something, but where did "25 hours" come from? Surely about 40 hours (or 5 - 10 hours before the skill test)
Slow flight stalling is about (depending on individual) is about 10 hours in. So after the solo circuit/rejoins etc, they go out in the local area for some general handling etc. Add all those up and it will be c.25 hours. Roughly that is, before someone starts getting ridiculous.
That is when I do not think its appropriate for these types of exercise.