That's great analysis!
However in my case I need every qualifying km in order to maintain status. Doing two long-hauls to the U.S. on LAN per year is just enough when one of these is in paid J and the other paid Y with a kms upgrade. I then use the coupons for a traveling companion on short-hauls within South America.

Edited to add: My new policy started last year is ZERO risk when it comes to my upgrade ---- it MUST be confirmed in advance or I don't go. This is the main reason I don't like Comodoro.