Just spoke to the CAA and and apparently if the mark is below 74.5% (i.e 74.4%) it gets marked down and if its above 74.5% (i.e 74.6%) you get marked up.
I should hope so! If i'd have got an answer of 74.6 in a question then I'd have gone for the option of 75 not 74!
Is the CAA ever going to get it's act together? I think not.