I'm unsure how or if there is a "separation." I'm sure providers would like to maintain a clear delineation between their business and residential assignments; however, I'd think it'd be difficult to maintain.
If a business switches from Verizon to Cox, I'm sure the business would want to transfer their Verizon business number to Cox. Would this number be in the business allocation of Cox? If a business wants a vanity number, such as KARS-4-KIDS, would this number be in the allocation?
I'm not sure how it works. I think the separation is just where the scammers get their dialing lists. I can't speak for anyone else, but it appears my spam calls have significantly dropped over the past year. Perhaps we're just in a weird cycle.