I'm still unsure as to how accurate this is. For me at least, I have 2 bars of LTE throughout the day, which iOS considers to be "low" and I'm sure most people do as well. Still, my battery life is generally great on my 6+. YMMV.
I agree. I never have more than 2 dots of signal and get almost 11 hours of heavy usage with my 6+. I'm sure a lower signal impacts on battery life, but not to the massive levels that some claim here.