not sure about this manipulating plan, but i'm in level 80 now, and i've never manipulated my teams at the end/beginning of season. I usually end the season between 130-140%; hence starting new season at 110-120%.
Yes, i've met tankers and +1 teams continuously every season. But i'm a league champion for 10 consecutive seasons now, and on my way to the 11th straight championship win.
Historically, i've won 56 league titles from my past 79 seasons. And i've promoted every single season since day 1 without manipulating.
So for the spirit of the game and to test your own skills and ability, why manipulate? Doesn't bring any joy, satisfaction and pride in winning