In my opinion, Latin can be extremely difficult. Sure there's no oral component, but the grammar is much harder than in other languages, and the lack of a distinct word order (particularly in poetry) makes up for this lack 
Also, we study the usage of the language (devices etc.) of famous Latin works
EDIT: Oh, and we do read Latin in our class 
yeah i have seen that word order, haha i saw something like literal translation of 'In Family Rome Is' with able to figure out it meant Family is in rome. Sure that's an very easy example but considering all that is needed is translating skills involving this, you can pretty much learn all with practice.
so if all the language devices are known of, and you can read italian quite well (the level expected of a year 12 student), there isn't too much reason that a raw score in the 30's isn't possible, right?
perhaps most students don't make this a focus and so haven't gotten to such a level of translating & rearranging sentences.. reallly doesn't seem that hard though

(relatively, any language is difficult to learn..clearly)