Given the short supply I guess they must have just finished putting your battery together at the last minute and the new paint smell hasn't had time to fade. Yeah it will definitely fade. Not seeing too much SOC variation (either way) is a GOOD sign for battery health. I'd be happy that the new battery is not seeing green SOC as often as before. Six bars (the top blue bar) is the preferred SOC that the Prius tries to maintain. What Ron said. The MPG calculation that the computer performs relies on stored "historical" data (that has been collected over a great many tankfuls) in order to calibrate the MPG readout. It's very common for the MPG readout to be relatively inaccurate for quite some time after the stored data has been wiped. Just give it some time, your new battery sounds like it's a good one and it's very unlikely that anything else would have adversely affected your MPG.
