Having been caught lying about if for months. Apple have fixed the 'Signal Strength Bar Display' – BUT ONLY because the got caught out! Tossers!
Details of the 4.0.1 Software Update for iPhone
This update contains bug fixes and improvements, including the following:
– Improves the formula to determine how many bars of signal strength to display
Products compatible with this software update: iPhone 3G, iPhone 3GS & iPhone 4