jigglysquishy on SSP made the observation that this possible height increase should be enough to have One Bloor as the tallest pure residential tower in North America.
The current tallest, built or under construction, in North America is Bleekman Tower in New York, at 267m.
The current One Bloor, at 237.7m, is 29.3m shorter. At 3.4m per floor, that's a bit less than 9 additional floors, well within range of the expected increase in number of floors if this rumour is true.
(Actually, Toronto does quite well in the 200+ metre all-residential tower race. Of the 17 towers built or under construction in North America, six are in New York City, four are in Chicago and in Toronto, two are in Miami and one is in Austin, Texas. One Bloor will make it five for Toronto.)