I am flying YYZ-GRU at the end of this month. I have already rebooked this flight twice in the past 3 weeks (as more lucrative seat sales warranted) in Latitude fares to take advantage of using SWU's.

Now I find that we have a 35% off sale but the actual fare cost in Latitude has gone up. However, if I book a leisure fare (and go out a day early) I can pay about 25% of my latitude fare.

When I look at the SSWU they mention many places where I can use these certs but other than Venezuela, there is no mention of any places in South America let alone Sao Paolo. Can I use the SSWU for this flight?

I've checked with an online availability tool and right now it shows I6 for the outbound flight and I9 for the inbound. I'm wondering if it is worth it to try and book and get the upgrade on the 19th (I'm only Elite, this is the last day of the sale and coincidentally 4 days before my flight on the 23rd) and then cancel my Latitude booking once successful.

I'd then have to hope I can, a few days later, also get the upgrade on the inbound flight. Since both flights are overnight I'd really like to fly up front.