Your escrow markers are what imho your basis in any payout will be!
There have been several charts that show payouts based on a per bill basis coming back here.
I have not kept up that much with commons since I only hold 22,000 so they are the least of my concern.
But there have been many references to commons on a per bill $ value coming back here, but honestly I can't give you that number off the top of my head! I think it is like .22 per bill or .33 I am just not sure