DD got an E in English (at half-term) with a note from the teacher saying that because they were still on KS3 (all the other subjects are marked on GCSE grade as they have started their GCSEs) they converted it to a 5A and as her target was 6B and she was doing fine.
At Christmas she got another E, I ignored it because it seemed fairly 'on target'
At Feb half-term she got a B; I congratulated her and rewarded her for such an improvement
It's Easter now & she got another E 
Apparently the B was a piece of GCSE work which was marked at GCSE standards and that's why she got a B
So is KS3 less than GCSE work? I don't understand this?