I know its the plus figures (xx + xx)on your planet screen, but does "Free" mean that they don't count against your income when calculating your decifit/surplus ?
the right-hand side of the + is indeed production/research which you do no pay for. An easy way to see this in action is to start a game with the technologist party and take maximum picks in research. You then set 100% research and adjust your spending until your only colony generates exactly 40 research points (on a large map, 50 on a huge map, probably less on a smaller map). By exactly 40, I mean that xx + yy = 40. To simplify the problem, set your tax rate to 0%. When you hit next turn, your treasury will go down by xx, not by xx + yy, proving the right-hand side is indeed free.