The longer you stay on the more risk there is bottom line. Are you willing to up the risk of not recovering and ending up on trt for the rest of your life?
Is that a real risk only running a 18-20 week cycle? People run 25-30 week bulking cycles all the time.
I guess a better way to word it would be: Is the chance of not being able to restart my HTPA substantially greater running a 20 week cycle as opposed to a 12 weeker?