Usually procedure is to throttle back before reducing rpm to reduce the chance going 'over square'. Eg 27" 2700 rpm on take off reducing to 25" 2500 rpm for the climb. ( 27" 2500 rpm being over square)
But if you look at the book over square is often allowed. Eg 27" 2500 rpm
So to reduce the fiddling of reducing throttle, setting rpm then increasing throttle your instructor is probably just short cutting the exercise. I used to do this in the bulldog and the Pitts all the time.
Read the manual , as I recall the bulldog would allow 29" 2500 rpm at sea level.