This is a "damned if you do, damned if you don't" situation for many service providers.
Some time ago, Anveo released price tiers for the US which allowed calls to high cost areas (at a higher cost), and actually LOWERED rates to much of the USA, to $0.005/min. They got flamed hard for this from the customers who used routes that went up by a fraction of a cent, and the end result was that they rolled back to the original pricing model. So, if this is an inconvenience for you, thank the customers who refused to pay pennies extra per month. The lesson to be learned is that insisting on the products and services you buy be as cheap as possible is not always the right thing to do.
If PhonePower's claim that they do complete calls to high cost areas at a flat rate is accurate, that's good PR. But they'll lose money on your account. I can assure you that won't last.