The FAA has refused to take action on cold weather corrections even though the subject became an industry/FAA forum issue in 1991, or so. After a couple of years of such inaction the U.S. Air Force pulled out of the discussions and stated they would proceed with corrections, FAA on board or not.
Granted, unlike Canada, much of the U.S. doesn't need cold station corrections, but the northern states, Alaska, and the Rocky Mountains certainly do at times.
Last winter a commuter jet almost hit a mountain in Vermont on an extremely cold day.
The big issue in the U.S. is a very stubborn controllers union.
Smart folks make additives from the IAF inbound. If there is an ATC conflict you tell them what you're doing and why. It really doesn't matter that much where the IAF is 1500 or 2000 above a flat-area airport, but it sure does where there are mountains around.