The base spell costs 3 RPs, and you get 1 POW and 1d8 mps ? Each stacked RP on top of that gets you the same. So, using 21 RPs should get you 1+18 POW and 1d8+18d8 mps? If my math sucks, pardon
Perhaps my example of the abuse wasn't the best possible, pardon that also. I just think the spell should have a limit on how many RPs you can stack with it, or the spell should be one use. It seems cheap to me, no matter how mortal the peril is, that you can just draw the 19 POW from earth and just pray your RPs back