Tbh just don't bother with the fourth AS it is not essential. Or do the EPQ in year 13, three As are better than like ABBC because you should get some high predicted A2 grades. I did three AS and Completed EPQ this year, got three As and five offers from Russell groups such as Warwick and KCL for History. Then there's people that did four AS and struggled and maybe even got one U which is worthless