post cycle would start week 15. dont like the idea of starting a week early especially if your gonna run an oral until the end. wouldnt hurt anything except your wallet tho so its your call.
im sure you know if your gonna lose it you are gonna lose it. all you can do is delay the inevitable. but like i said you went from one of the worst cycles for hair loss possible to a much much milder one. with the addition of nizoral and a pct you should have little to no issues with this one.