I would think they'd be glad to do this. Having a fixed IP assigned means their stock is reduced even when the owner of the fixed IP is not using it online. Having a VPN owner get a new IP at every connect rather reduces, from the provider's standpoint, the service they offer without having to reduce prices. In other words, it takes the fees for increased VPN service and provides lower-grade plain vanilla services without fixed IPs.
Just a quick thought.