Your first calculation did sound low but I accepted it… your second one is high! A 240 lb man with 20% bf has a LBM of 192 lb, and that times 12 cal/lb, gives 2300 calories. This works very well for fat loss. So the difference compared to what Will is recommending is 400 cal. That will work faster but will also slow the metabolism more. Personally what I’ve seen with many people is that you get at best maybe half the benefit you’d “expect” from dropping the calories, sometimes none, and sometimes even an inverse effect… someone can hit a plateau in bodyfat at which point they simply lose LBM (for example, most anorexic women are about 20% bf I have read! Though at 70 lb, 20% is only 14 lb of fat) and don’t lose fat. Whereas with higher calories, they can continue to lose fat below this plateau. This is not unusual with women, and can happen with men as well. For example, take a look at pictures of male concentration camp survivors… they’re carrying subcutaneous bodyfat just like the anorexic women.
I’m not saying that Will’s formula pushes you way in that extreme because it doesn’t… it’s just moderately more aggressive (still has 82% as many calories as what Lyle and I prefer.)