D.K.
I used mine in college as my desk chair and loved it. I know I moved around more when on it too. Can't say for sure about abs, since I did gymnastics and we did a lot of abs, lol. My parents were up visiting our house not too long ago and I had my mom sit on mine for awhile and she seem to be able to feel it when she got up. I use mine now to watch tv sometimes too.
I would think it could help, especially if you move a little here and there, since your muscles will automatically contract to keep your balance. Sounds like fun being able to use one in the office place as a desk chair!