been having that issue I discussed go on for years, always thinking I solved it, then it would happen again. Turns out there is a managames topic about it: http://www.managames.com/Forum/topic5-16488.php
I changed my "TimePolling" in Tennis.ini file to "TimePolling=2"
To test this, I played a match (decent player) where I left it at "TimePolling=0, and it was awful, my ball floating. I barely won set. Then I changed it to "TimePolling=2" and game sped up and I bageled him. I'm posting this in case others are having the issue.
Pizzout