You can always adjust to do just well enough and close to par, but if you're trying to make money, while you're grinding your way to 205, someone else is going to have that match up for a 260 look on every type of condition in any house. Part of being a "great" bowler in today's modern game is sound understanding of your equipment in relation to what's out there on the lanes.
It doesn't mean you have to bring 6-8 balls to league. As a matter of fact, I see guys bring 6-8 balls to league all the time, and they only throw the newest ball they have even if it doesn't work. But the truth of the matter is, what's going to take you from shooting 230-240 to shooting 279 and making $300-500 in a league night, unfortunately is going to be proper ball matchup in some cases.