I'm not sure I understand what you are tracking here, please correct me if I'm wrong: 'loads' counts how many times that mode+map are loaded in a server, 'joins' counts how many players join while that mode+map is running, and 'leaves' counts how many players leave while that map+mode is running.
I think that the net people per load isn't the best way to rank the map+modes.
Net players (joins - leaves) provides a more meaningful ranking because it shows how many people joined (or left) the server because of the map+mode.
Sorting by number of loads is interesting also, especially for high ranked map+modes with negative net values.
It will be interesting to see the results from tracking map votes.
I think that the net people per load isn't the best way to rank the map+modes.
Net players (joins - leaves) provides a more meaningful ranking because it shows how many people joined (or left) the server because of the map+mode.
Sorting by number of loads is interesting also, especially for high ranked map+modes with negative net values.
It will be interesting to see the results from tracking map votes.