Signal Strength Question

[testacon]

I get the basic gist of what a decibel is and the range that it uses to determine how good your signal is to the tower.

What I'm wondering about is, between multiple Epic's what should that range of signal be in the same general area? I have two phones and can typically see a 5 dBm difference between the devices when next to each other. Since I don't know if that's a acceptable plus or minus tolerance between the two phones I'd figured I'd ask what other Epic owners have noticed. If one phone is sitting at -89dBm, the other phone can sit at -93dBm which is obviously a lower signal to the tower. Is this worth a warranty exchange? Is this something that I can get fixed by reflashing the radio? I think my phone has been roaming WAY too much compared to my previous PPC6800 ever did. Could Sprint's coverage in my area taking a nose dive in a month since I've switched phones Any other suggestions?