i have a 175 merc and my buddy has a 200with a trophy 25 4 blade he turns 6k and runs 72 i put his prop on and turned it 6k and only get 64. does 25hp make that much difference? exact same boat only diff is his motor is 3/8in lower. i just think my boat should perform a little closer since i am turning his prop the same as he is. any input would be greatly appriciated.