DS isn't interested in his "scaled score". He's interested in his test results, and he wants to know "how many did I get wrong?". For that we'd need to know what the maximum number of marks were for each test. Can we work backwards from the scaled score to get this?
e.g. in maths he got a scaled score of 116 out of 120. Does this mean he scored 97% on the test? His test result was 106, so if that was 97% it implies the max number of marks was 109. So can we tell him he dropped 3 marks?
It would seem logical, but I know standardised results can include jiggery pokery so maybe not.