Hey ash,
I wouldn't worry about the hairline crack. I've seen many balls (various manufacturers) that this happens to and have lasted, plus your warranty is up and it's plugged. If anything, take it in the shop and maybe have your driller hit the finger hole with the bevel sander and try to round it a little more.
I wish I could show you guys the material that's being used to create our lower rg balls these days. It's really, really light. If you ever get a chance, tell your shop guy to save a piece from a bridge that cracks out and you can see what I'm talking about.
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Rick Leong
Ten Pins Pro Shop
Track Intl. - Amateur/Pro Shop Staff
Vise Inserts Staff