thanks meta, i guess my brain was fried after a long day of work and i just missed that line.
Anyways, I tested it. I put my phone in field test mode, and it read -70. Then, I put my phone in the cradle, and it still read -70. I then proceeded to make a phone call to see if that would change anything. Nope, after the phone call, it still read -70. (I'm pretty sure when I was actually calling the person, it switched over to the normal bars).
Perhaps -70 is the best signal possible? Or maybe it works better in a spot with poor coverage?
(This test used a Verizon iPhone 4S, and a 2012 X3 with dock and bmw apps)