YMMV, but to my knowledge no carrier will automatically process and allow an early upgrade within 90 days of the most recent phone activation (either new activation or upgrade). If you're at a retail store, the rep may have to call carrier services to unblock the early upgrade. If you would like to do an early upgrade via webstore, call customer service (or contact via facebook or twitter). With customer service, a level 2 rep can deplete the tab balance and apply it as an account charge manually in order to enable the early upgrade. As per the wireless code, you can buy-out your device anytime by paying off the remaining subsidy (tab) balance.
The only possible exception to this is if you're trying to upgrade more than once within a given billing cycle. You could port out and then come back for a new activation within the same billing cycle, but you'd lose any grandfathered plan or personalized offers, and Koodo could charge you back on any activation incentives.