I think all of the Nike balls have a Durability rating of 2.5, which is good for 120 hits per ball.
Putts don't count as hits, unless they are Practice mode Mulligans which decrease Durability by 2 hits for each stroke - including putts..
So your scoring average effects how many 'rounds' each 550 credit Nike will last.
I typically shoot about 62 for 18 holes and 25 of those hits are putts that do not reduce ball durability, so ball life is reduced by about 37 hits per round. 120 / 37 = 3.2, 18 hole rounds per ball as long as a ball is not lost OB, in the water, or in the weeds.
Your scoring average is about 75 for 18 holes and about 30 of those hits are putts, so about 45 hits get taken off the ball durability per 18 holes - 120 / 45 =2.66 rounds per ball.