I used to be really bad about eating at night, mostly because for the majority of the time, my schedule was to where I was asleep for most of the day and shortly after I woke up, I would eat dinner.
My nighttime eating wasn't nearly as controlled as yours is, though. It was more like binging, even though it was my 'daytime'.
From what I understand, it's not so much you shouldn't eat at night, but really just not right before you go to bed, because you're body, after winding down, prepares to store the calories you have just consumed for the 8-ish hours you are about to sleep.
My rule of thumb is mostly not to eat if I feel tired, sleepy, or sluggish, since I see it as my body preparing for 'hibernation' and will store what I eat as extra fat for extra energy when I wake up. If I feel like I could stay up for another three or four hours, I will get a healthy snack, like some grapes or oranges, or half a sandwich and eat the other half for a mid-'morning' snack, about halfway between breakfast and lunch, or when I get back from my walk after breakfast, when my metabolism will be at its peak.
If I do start to get the munchies when I'm feeling tired, I'll get a bottle of water and distract myself with something fun, such as pinterest or other things, until the craving goes away which, after the bottle of water, it usual does.