To me, Regrowth seems priced well out of range of its utility, especially when forms of injury tolerance like no vitals and no neck are only 5 points each. I am thus re-pricing it. After all, what is regrowth other than Injury Tolerance (dismemberment) that takes a very long time?
Regrowth can be faster than the default with a suitable enhancement. This is treated like an equivalent level of regeneration, except that no wounds are healed. Instead, it only determines the time it takes to regrow that body part. The value of the enhancement is equal to the cost of the equivalent regeneration advantage (for example, very fast regeneration costs 100 points, so very fast regrowth is a +100% enhancement).
When combining regrowth with regeneration, after one regeneration time step, a minor body part or extremity will be completely regrown, while a major limb will be short and an eye will have bad sight (both nearsighted and farsighted). After two regeneration time steps, a limb or eye will be fully functional.