I assume 64 is including the bonus Scholar gets from Light Arts, so Regen V would most likely restore < 48 HP a tick on White Mage before figuring in equipment and such. Still a step up over Regen IV, but not that drastic.
If the Stoneskin effect from Solace is added in and Regen V is assumed to remain at 64 MP a tick, Regen V would only be a smidgen over twice as MP efficient as a good Cure V. Twice as efficient is significant, but I'm guessing it's not the enormous difference one would expect just looking at "4,800 HP recovered".
Edit: I knew that number seemed too big. So, yeah, Cure V would actually be far more MP efficient than Regen V and I believe several other cures would beat it as well.