year 9 exam results, new GCSE levels

[jaws5]

DD's exam results in main subjects are
English 4
French 4+
History 5-
Maths 2+
Science 4

it seems very low to me as she finished year 8 with levels
6b in English
4a in French
6b in History
5c in Maths
4 (new GCSE level) in Science

Should I be concerned?

Providing their working hard, they are expected to go up a level a year. The one subject I'd be concerned about is maths, why is there a significant drop in that subject.