It may be more difficult than a relatively static price, but if they can figure out how to charge it, they can figure out how to display it. Any ISP sites I’ve used have you put in zip code anyway to view services. There’s no reason they can’t set it up to show the exact fee rates per area. I know you said you’re not defending them, but “it’s hard” isn’t really an excuse.
It may be more difficult than a relatively static price, but if they can figure out how to charge it, they can figure out how to display it. Any ISP sites I’ve used have you put in zip code anyway to view services. There’s no reason they can’t set it up to show the exact fee rates per area. I know you said you’re not defending them, but “it’s hard” isn’t really an excuse.