My 7525 type printers have had their toner dropping to 1% (always 1% and 268 pages remaining) very often, possibly every time though I can't confirm. The toner is clearly not empty, and usually will last for a while at 1%. This is the 006R01513 reorder number toner.
I'd assume this is either a software issue, or something to do with the black toner changing since it seemed to happen suddenly after a reorder a few months back.
Any idea how I can get my printers to stop giving the wrong readings?
Did the tech fixing the non customer mode issue have any thoughts on the issue while he was there?
Have a tech look at the toner gauge nvm's. They were probably set to default when the battery died.