Welcome aboard mate. I've been having this problem ever since I started playing. I really don't know why I keep beating my head against the wall either, I guess I'm just not too bright.
I've tried everything, empty cache, change browser, close all other programs, you name it, nothing helps. I notice it most often on drives off the tee but it lurks waiting to strike on other shots too. I've actually seen the meter jump from the first (left-,most) bar to the last (right-most) bar on the meter. I have no chance for good scores. It's more that frustrating.
I have a brand new Dell I5 processor with 8gb of memory. Maybe you have to donate some cash to WGT in order to improve your scores and get a smoother meter? I refuse, after all they tell you, enjoy it, it's only a game.
I suspect this is a known issue with WGT but they choose to ignore or deny it. Let me know if you ever stumble across a fix.
Good luck.