Are you suggesting the TAB aren't being honest in applying the deduction formula?
Otherwise, surely you can work it out for yourself. Using my bet above, (Expected collect minus actual collect) =800-480 equals 320.
Then you divide 320 (the difference) by 800 (the expected collect) which equals 40, so you know the price must have been 80 (as per the formula) divided by 40 = $2.