Sometimes your coursework results are lower even though the moderator has not adjusted them, or lower than the scaling applied by the moderator. This is due to the impact of UMS, which depends upon where the boundaries for a unit (in any subject) are set. Thus if the boundary for an E is 45 rather than 40, anyone on 45 will be moved to 40 and anyone lower will also drop. It also impacts on marks in between the A and E boundary. It is very complex to explain but exams officers should be able to talk you through it.
there are various explanations online, none of which are entirely satisfactory, including a youtube video. A search for 'uniform mark scheme in google will take you to some- take your pick for which makes most sense!
From Rob Carlton: "Form Rob Carlton: From a quick read of some recent posts it seems there is some confusion over the UMS mark system (employed by all awarding bodies).
It is important to bear in mind that nobody can lose a grade through the UMS conversion process and no candidates are disadvataged.
If I take for example, the grade boundary for a grade A this summer for Unit G321 (Foundation Portfolio) which starts at 81 raw marks; if a candidate scored 81 raw marks their mark would be converted to the same point on UMS grade boundary (the UMS grade boundary is fixed for the life of the specification). Grade A on the UMS scale starts at 80 marks out of 100 so the candidate's raw mark on the boundary of 81 in this case would convert to a mark of 80 UMS and they would still receive their grade A.
OCR have an explanation of UMS for teachers and parents posted here
or if you prefer, OfQual's explanation is posted here (see pages 12 and 13 of the document)