I m pretty sure you get a hidden penalty for changing time. I ve noticed too that every time my team performs awfully. That s why i try to move alwais league matches not touching cup or cl.this season i had to move 3 games all vs bottom tiers teams with an avg Q AROUND 15/20 points less than mine, and in all 3 matches i ve struggled against them (2-0, 2-0, 3-0).