Jeff,
Perhaps I'm overlooking something. I don't see a "Client Coverage" dashlet.
Although if you're reffering to the "Coverage Area" dashlet mine seems to be accurate. I've referenced it against the client list on the controller. I am also running version 1.1.0.58.
Also, I've done a quick search for a bug about this but wasn't able to find any.
How far off are your client counts?
Regards,
Aaron