I would say the strategy, if there was one, isn't working.....judging by this e-mail.....

You now have more time to request upgrades prior to your departure, offering you added flexibility when planning your trips. This offer applies to requests made between March 17 and September 5, 2016 for eligible Flex fares for travel within Canada, or between Canada and the U.S. or Sun destinations.


Usually the dates are only for summer travel. Not spring and summer.