In the press conference Apple gave on July 16 about the iPhone G4 reception issues, they basically said that the 4 or 5 bars you usually see where fake, and caused by a "bug" in the way signal strength is measured.
If I remember correctly, there was another "bug" with the reception prior to iOS 4, that was solved by a software update "improving" G3 reception.
I can't help thinking they just tweaked their formula to show high bars to save their asses, and this backfired on them with iOS 4.
