Its becuase it takes longer to clear your system. This way, 2 weeks after you last test shot you start PCT which would give the deca 4 weeks to clear your system. Have you read up on PCT? Also what are your stats and cycle history, it sounds like you havent read to much up on this but i could be mistaken. Another thing, you are depending on way to many compounds when everything you can achieve is thru ur diet.