I think it would certainly make your job easier to understand what's in the mains and how that reconciles with the government's priorities expressed through a budget.
Right now, I think having the mains reflect only part of the government's priorities is not very helpful, because a chunk of it has to be found in the in the supplementaries. So having more, if not all, of the budget money in the mains would make your job—and mine too, to be honest—easier.