I hate you now. I walked up to the top floor of my apt building, took off the phone case, and just hit the 5 bars threshold with a signal strength of -85dBm on the 4G side. Best I could get is what u see above.
HOWEVER I do know I am smack in the middle of two Verizon towers that are both approx 8mi away from me, so 16mi from each other. I do notice when i'm in my apt downstairs that the signal will drop quickly and go to 4 bars and then drop again and go to 3 bars and then go back, all the while staying 4G. (It only does this, once every 30mins or so)--found out it was switching only when I was using it as a 3G hotspot when I first moved down here, then I noticed it on occasion, if I was looking.
But now I only notice the change in towers when I look at the phone's status screen, and look at the IP address. I could be wrong, but a phone, staying on one tower, switching IP's, while having signal strength fluctuations, can only mean i'm switching towers. Since I use Comcast I can't give an accurate up-time with a single tower, since I no longer use it as a wifi hotspot. But the huge speeds I did get in my original post, I was less than a mile from the one tower on high(er) ground....while driving too.
I notice that while driving I always get much slower results.
OK enough of my rant, you have a better fiber backbone than I do....