I don’t think that he's talking about the battery dropping to 98% after removing the charger. He mean that during charging, his phone never goes above a certain percentage no matter how long it's left on the charger. My phone never went above 94%, first I thought it’s because of the firmware but it was not. So I dropped at a Sony service center and they told me that they had to change the motherboard. It was for free, so if his phone is still on the warranty might as well go to a certified service center and deal with it.