I have a companion pass through a premium credit card.
So I can book any economy fare for myself and my companion.
So I often try to book latitude fares, and then try to upgrade then and there
I save money on the company's ticket

But of course, the ability to upgrade at the time of purchase depends on at least R availability- and perhaps additional availability through a proprietary formula only known to AC/Aeroplan executives.

Yesterday, I was checking for trying to see if here were any such upgrade availability for many transpacific routes- including those to Singapore, Bangkok, Hong Kong, Manila, Sydney, Brisbane, etc- no luck in many random dates in 2026- until the last date bookable.
There was some R availability for Feb 2026 for Narita.

I did not check for Seoul.

So the question is whether the AC flights to these destinations are ever upgradeable on the date of purchase using a latitude fare- whether or not R is greater than 0.