Sust works best on higher calorie diets, the stuff that does work on low cal diets doesn't make much muscle. However that is what is generally said, I've never tried to cut and get bloated at the same time
With being 12% bodyfat, why are you trying to cut up more? I would probably do them seperately, run the sust now for whatever weeks, and then cut after.
With only 250mg a week, you probably wont see alot of water or muscle gains though, it may be enough for small gains coupled with keeping your muscle as opposed to losing it, so maybe based on that its a good way to lose fat while not losing muscle. Keep using the calipers, if you use the scale as your guide it may deceive you.