You say the cost of running Bramall Lane on match days must be profitable, but by saying that you are doubling up on the takings for the day because the income from the day is already included in the £20m income in the accounts.
People are making the same mistake with things like club shop sales. Yes, the shop may be profitable, each item may be being sold at a profit, but that profit is already accounted for in the income, an income that is being used almost entirely to pay for wages. That leaves the costs of buying goods, operating the shop, operating the Lane on match day, etc, to fall into the overall costs.
I'm not an accountant and would also love to see a breakdown of costs, but not because I think there's something dodgy about it.
We've been quoted the cost for policing on another thread, I can't remember it, plus there must be various other fixed costs to running a football club that I can't think of. For example, is the stewarding outsourced? If it is, the stewards won't be part of the wage bill, the company's invoices will be part of the costs.
etc. etc.