Well, I simply cannot disagree with all the statements mentioned above - I was of the same opinion when discussing it with the instructor. Anyway, take -off power setting for this a/c is 38 inHg and 2600 RPM, so it wouldn't be so dramatic when reducing to 2500 RPM first, as it's not so big difference. The wisest thing would be though, to leave this power setting sequence the way my instructor wants and after the exam just do as the manual and the common sense says. I just wanted to be sure I wasn't missing anything
I believe that my instructor is extremely professional and maybe he has a bit different considerations, which I don't understand at all