The Missing Limbs thread got me thinking about this. Suppose a guy who is pretty good with Creo/Corpus/Mentem invents characteristic boosting rituals, to raise negative characteristics only. He's fairly old, and this is only for his personal use, but the idea is that he improves to what he was in his prime.
In our example, he has a Str of -4 (due to age) and has 3 Aging points in it. What happens to those aging points when he uses the ritual? His Str would go to -3 and he would have 3 aging points. Would you keep it as that, and on his next aging roll where points are supposed to be applied to Str, just adjust Str back to -3, or would you do it right away, once the ritual has been completed? In both cases, the ritual would need to be performed twice. Or would you choose super secret option #3 and eliminate all the aging points when the characteristic value changes?
My instinct is secret option 3, this person has spent a lot of vis and time researching the spell (and wil warp if they are comissioning it). I would not change any accumulated decrepitude points (I know you didn't mention doing this)
This means that Magi die from 5 Crises or Twighlight, not random bones snapping.
I agree, creo rituals are an act of bringing someone close to the ideal form so I think that the aging points would be lost in this case and given the rediculas expense of casting this ritual, I don't think it is overpowering.