Well first off, it's best before bed because you want to slow protein digestion at night. Some EFA along with a slow digesting protein source, like tuna, will help prevent nightly catabolism.
Second, for myself at least, my early meals consist of carbs. You don't want fats in your first meal anyway, because after a night time fast, you want protein into your system A.S.A.P., thus a scoop of whey with my morning eggs. The other meals in the AM tend to be carbs, so I don't eat them late at night and don't store as fat.
That second one is dispelled if you don't buy into avoiding the mix of carbs and fats though. In the end, when isn't going to make the big difference. Whether or not you use it will, and even that won't be huge. Don't fret over small things.