One of the advantages of TubeAssist, is that all sending happens from our servers. So this means your table or cell phone's data plan won't be impacted by using TubeAssist.
The only way you could use a little data on your tablet or cell data plan would be by visiting https://www.tubeassist.com on your tablet or phone. Doing that would use no more data than visiting any other typical website on the internet.