Why are the values in the “Registrations in Visible Area” adding up to what I see by clicking on all visible balloons?
The numbers labeled “Registrations in Visible Area” in the side bar are based on adding up registrations from any tiles that the Google Maps implementation is using in the current display. In some cases, only a small portion of a tile is actually visible, but all of its registrations will still be included in this side bar summary. This trade-off has been made to keep the “Registrations in Visible Area” feature running as fast as possible.