final exam and prelims

Honestly for me I think the amount of revision fully depends on the depth you already understand the knowledge. From my personal experience, I always find the prelims quite a bit harder than the final exams (usually the amount of knowledge on specific areas is a lot more). For someone who already has high grades in the prelims, I would say do around the same amount you are already doing. Usually students will go up a grade boundary from prelims to exam times with sufficient revision. At the end of the day you should be really proud of yourself for getting As already as that is a really high grade!

I agree, if the gap is very close to 85%, the current amount of studying should work. But also, I should really stress this, PAST PAPERS. Just staring at notes isn’t going to help much (I’ve found that personally to be the case). But yeah, those are quite good grades! Better than some people I’ve seen at least :P
Just make sure you don’t stop revising and continue doing past papers!

What level are you currently studying at? (Just asking cause why not)