Polish? What polish?
Everything I've read about it says the stock surface is 2000 grit dull/matte.
Did you add polish? If so, you added backend.
Any surface change to add backend is going to make it handle less oil: polish or taking the cover to P4000 grit.
You could have drilled it with a lower VAL angle, but I'm sure you don't want to redrill it just to do that,
You can also add a flare reducing weight hole, but will also reduce its oil handling ability.
"None are so blind as those who will not see." "Some bowlers are crazy as pickled cats."