Apple is now placing the blame on AT&T by saying that the problem is actually low bars (i.e. the network).
Brilliant way to shift the blame.
If you don't remember, back then every blogger was saying things like "my signal has improved drastically with this update!!11!!1one".
This is what the graphical representation of that update was: http://fscked.co.uk/post/754590440/this-infographic-hopefull...
As you can see, over 50% = 5 bars. AT&T's recommendation = more accuracy and less reality distortion.
Next update, you should see OS 2.1's 3g signal update reversed to what it used to be.
Edit: dBm as a unit for SNR doesn't make sense, which is why I was confused. The Y axis is overall signal strength, not S/N ratio.