Actually, drilling out the Mass Bias in any hole will increase the intermediate differential, thus giving more reaction than before. If you look at the 3rd asymmetrical layout of this page:
it shows that the undrilled bowling ball starting at .015 intermediate differential and .048 total diff is then increased to .026 and .055. Way stronger in motion than once before. Evidence of putting the preferred spin axis or mass bias near in the thumb hole increases motion, is also found in the symmetrical ball layout on that page when the undrilled ball starts at nearly zero intermediate differential and .054 total diff is increased to .013 int and .061 total. Way stronger in comparison.