Well let's say you're cutting and you're wanting to keep your cals 600 below maintenance. Do the math here. If you're working out you're burning more calories, so your maintenance cals for the day (example) is somewhere around 3,200 lets say, so you cut to 2,600. Then you are on a rest day and aren't burning those cals from a workout so your mainenance cals for the day is more like 2,800 so you cut to 2,200.
It's really simple dude. And remember those numbers are just examples.