Apple:
Upon investigation, we were stunned to find that the formula we use to calculate how many bars of signal strength to display is totally wrong. Our formula, in many instances, mistakenly displays 2 more bars than it should for a given signal strength. For example, we sometimes display 4 bars when we should be displaying as few as 2 bars. Users observing a drop of several bars when they grip their iPhone in a certain way are most likely in an area with very weak signal strength, but they don’t know it because we are erroneously displaying 4 or 5 bars. Their big drop in bars is because their high bars were never real in the first place.
That certainly explains a lot of tints over the years. Also this is Apple pushing the blame to AT&T and not contradicting what Jobs’ has conveyed in emails to customers (notice that Jobs did not sign the letter). This appears honest and offers a fix, It is not OK, but it is not wholly inexcusable. Apple should have caught this 2 years ago and they didn’t, when they did catch it they are fixing it.