I was in an older (1980s) apartment building so I couldn't blame a singular meter, I'm not really sure how measurements are done in big buildings (maybe someone could explain?).
I've heard that elsewhere in Ontario, Canada and in Toronto (two different companies) that overcharging is a big recurring issue. I wasn't given a good explanation about my one anecdotal case outside of an 'accounting error'. I just knew that it sounded far too high to be normal.