Replying to Does 5mm make that much of a difference?

alright so this past season my friend had the 175 arv. i dont know what the waist but this year it is 92. this year i am looking to get the 170 msp and last year the waist on those was 87. me and him pretty well ski the exact same stuff and he never complained at all that they were bad for powder. so i was just wondering, if he doesnt have problems with his 92 waist in powder, would a 5mm less waist difference make a difference skiing?