You're approaching this way too systematically. Firstly, revising 16 hours out of 24 seems like way too much not because you can't but because you're going to overwork your brain and basically not remember information as effectively - in order to combat this, however I do hope you take regular breaks a couple of times an hour.
Secondly, when you say A levels, I really hope you mean AS or A2 and not 4 full a levels, damn son. In which case I don't think you'll find anyone else crazy enough to attempt this suicide mission!
How do you also revise? Are you attempting to go through all 4 subjects in a day or do you do 1 subject per day or something. Joke aside, this honestly seems ridiculous.
Lastly: you have beautiful hair.
EDIT: ALSO WHAT ABOUT COURSEWORK?! I'm pretty sure OCR and Edexcel (and maybe/probably others too) for Biology and Chemistry have some sort of coursework or controlled assessment. You seem to be self-teaching.
wat