Just got an S7 and when trying to conserve battery life by turning on airplane mode...in other words cellular off I tried to make a call and it brought me to the WiFi calling setup screen. I didn't know this existed but now know you can do EVERYTHING via WiFi, phone calls, texting, even MMS texting. So, my question is which is better on the battery for phone calls and texting? WiFi on and cellular off? Or turning WiFi off and just using cellular? In case it matters, let's use my home for example where I usually have one or two bars of cell service. Obviously perfect WiFi. I have Verizon also. I just tested, fluctuates between one and two bars which is beteeen -114 and -118dB signal on the "Network cell info LTE" app also showing 4g signal.