An extra return air grille and round 12" duct can be run from the attic down past the unit to the base, giving you better return air. Place the 12X12 grille in the master bedroom or relatively far from the existing unit. Again, you are over-cooling the house with all that tonnage so something needs to be balanced out.
Be sure you have opened ALL of the air vents in the house, even in rooms you may not use. Adding another duct run or two may take some of the static pressure off the current runs a bit. You could run another one in the den or kitchen to make up for the difference.
Great bill, by the way! You are cooling the house so fast the darn thing doesn't have to run a lot. What Brand and SEER rating did you get?
Last question...was this 5-ton replacing a 4-ton previously?