Nextel Tx/Rx Signal Strength Data

Here is my situation: I'm currently using a Motorola i355 phone and am trying to confirm what a certain set of numbers means. After I put my phone in Trace Mode, I see 2 options (Tx Status, Rx Status) which I'm guessing mean Transmit and Receive. Upon selecting either of these options, there is a pair of numbers on the second line that look something like this (-00 -82). When the second number gets down into the -70's, I notice the first number begins going up - I've seen the first number range between -01 and -16.

Here's my question: Am I correct in my observation that the second number is the signal strength, and the first number is a reduction in signal gain once you get closer to a tower, almost like the phone doesn't need to transmit at full power and can attenuate some of the signal?

Thanks,
Curt