Trying To Understand Calling Over Wifi

view story

http://forum.xda-developers.com – I have been using Talkatone for it, but recently, I was wondering about the the native option. I do have the TMO S3, with the wifi option enabled in my rom. I have my Google Talk and Voice both set up correctly. But when I use the phone icon to make a call, my minutes decrease. I thought by using wifi, like I do with Talkatone, I wouldn't use my contract minutes. Sent from my SGH-T999 using XDA Premium HD app (HowTos)