If you suspect that one of your player's average is wrong here is what you can verify:

1. Do you have the Remove ERO Against option turn on?

We have an option to Remove ERO against. Which means that if a player got an ERO against him, the games and points of that match don't count for his average. This way his average is not affected.

Go to Stats Model Editor (Menu > Manage > Stats/Standing Grouping > Stats Model Editor).

Check to see if the Remove ERO Against box is checked.

If you want the ERO Against to count and affect the player's average. Uncheck the box.

Another way of checking is calculating under Stats/Standings > Singles