stomach re-shrinking

I'm targeting 18-2000 calories a day and notice that I have slipped up to
the range of 22-2400.

The first week of "dieting" was hell because I had to get used to the lower
intake. I guess that is about how long it takes for a person's stomach to
shrink, based on such a significant change.

I'm wondering if I can do the same kind of thing, maybe go through another
hell-week and shrink my stomach again. I think this would be much easier and
better for me than going through a constant 400 calorie/day battle.

Should I cut back to 12-1400 calories/day for a week and then gradually
increase my intake? Maybe doing something like this every several weeks
would really help to keep me on-track.

I am currently somewhere around 260 pounds (best guess), and I walk 3-4
times a week.

Thanks!