The new 78 hardness ones really need 500 or lower to be effective. I've got a local PBA guy and he hits his black hammers with 180 on the resurfacing machine before drilling them, and leaves them that dull. They look hilariously chalky, but that gets them to read early enough to shape.
I've done similar with Tank Rampage Pearls, I don't have high rev rate, but don't have high ball speed either, but 180 grit on them works.
OOB companies know they are a bit niche, and there's people that are buying them that won't use them on intended conditions so they don't release them any lower than 500, and the ones that know when to use them will tinker with surface finish anyway.