Regeneration (Radiation) - that Doesn't heal permanent rads

[JCurwen3]

Regeneration has the modifiers Heals Radiation (+40%) and Radiation Only (-60%), both of which heal rads and remove even "permanent" rads.

Any thought or ruling on what it should be worth if it didn't heal the normally permanent "10% of the original dose [that] never heals" (p. B435)?

And I guess as an aside, what the cost should be if a character has a normal healing rate for radiation (no regen) but can heal all of it (no 10% permanent rads)?