Louie,
Don't beat yourself up too badly about this. It happens. If you would have tried to be more aggressive, playing the drier boards, you could have been leaving 10 pins or 9 pins as well. It happens to the best of us.
I have had a fair number of 800 series in my career, but I have also had at least 3 occassions where I have had 570+ after two games and not shot 800. Sometimes as the lanes dry, you miss a move, or your carry just goes away, and no matter what you try you can't get it back. Just continue throw good consitent shots and one day the god of carry will smile on you again and you will get the 300/800 (or both) you are looking for.
Jorge300