I find the total stat very useful as I work. It works great if you collect all your hits with Panda Crazy because it will just add the reward to the total. Sometimes you collect hits outside of the script and that won't be added up. There is a way around this problem if you also downloaded the Panda Crazy Helper script. If you have a script that shows your P.E on your dashboard then the helper script will read it and send it to this script and update the P.E. stat. The helper script can't add up the P.E. so you need another script like Mturk Dashboard, mmmturkeybacon Today's Projected Earnings or MTurk HIT Database.
Once the script knows the P.E. then it just adds all the hits you have in your queue and updates the total stat. You can click on the total stat text to show either the P.E. or total stat.