Front Camera: 4S vs. 5S

I FaceTime/Video call a lot. I think the front cam of the iPhone 4S is about .3 MP, and the 5S is 1.2 if I'm not mistaken.

Im just wondering if video calling with the 5S will consume more data due to the higher quality front camera. I have 2GB per month, so...just outfit that out there, idk....

So does the 5S use more data for video calling since it has a higher MP front camera?

Thanks