You have a good mix of balls and consequently their reaction.
So therefore at 170 average, there's some things that probably need to be worked on that do not
deal with ball choice.
Since I was at 170 and can still remember that frustration I would suggest a coach and these goals.
1. how to get lined up quickly once league starts. This includes how to warm up and enter league play efficiently.
2. how to concquer the 10 pin leave (RHder) and get a strike instead
3. how to follow lane transition and stay in the pocket all night long i.e. lane transition
4. how to get secure on multi pin spares when you leave them (like the bucket).
5. get very secure on your 10 pin spare and 6,10 pin leave.
A new ball will not solve these issues. When you get to the point where you leave only 1 split a night and maybe one other open a night (maybe two) then you can look at another ball. Otherwise there are things to work on that have nothing to do with ball choice.
Erin