The IR (A) rating has 7 exams....end of! There may be 10 subjects, but there are 7 passes required to have IR (A) theory.
I too thought it was 10 exams for some reason...May some of the exams are combined. I thought the layout was:
Air Law and Ops Procs are two exams.
Nav is two exams (Gen and Radio)
Aircraft General Knowledge is two exams (Systems and Instruments)
Live and learn. Would explain why you have to do the lot again for the ATPL.
Madness!