A supplier who wants to switch from pay-once to pay-monthly is either going to be charging me less or charging me more.
If they claim they'll be charging me less, that leaves me confused as to why they think the change is in their interests, unless they actually anticipate charging me more.
If they claim they'll be charging me less, that leaves me confused as to why they think the change is in their interests, unless they actually anticipate charging me more.