Doing easy math since you have to account for the inital cost... you would loose a total of 66-10((8-7)*10) meaning total cost is 56 cp just to wait for 10 steps. At the 25% proc of good we would get 2 procs (since you can't double proc) netting us each 27 cp. 27*2= 54 cp. RNG could bless you but it's a gamble