I'm about to book YYZ-CPT in November. My TP year ends Nov 8 so the flights will count for next year's renewal. Am I correct in thinking that in order to keep silver for next year, I will only need 450 TPs as long as they are earned by December 31, 2022? Or will I need the full 600? If the latter, I'll book a roundabout route for extra TPs.