We never tinker with any swing changes during the season
I always see this. Not sure why. My son would tinker in between innings 
My son decided to change his swing with the first LL all star game when he was eleven. It was then he decided to wave the bat and swing from his heels like Gary Sheffield. In the stands I said to myself, "What the hell are you doing?" He hit a one hopper off the fence for a double.
A friend with a son on the team knowing I wouldn't yell anything asked if I wanted him to yell something the next time my son came up. I responded, "Yea, go Sheffield."
The next at bat he tripled off the fence followed by a homer that cleared the maintenance shed behind the fence for his first LL homer. He never used that swing again. He went back to his traditional swing the next game and continued hitting well.