I think Entropy is correct.

CO does not have a level over 75k miles - so you lose a benefit right there.

Also, with the exception of the ERJ flights down to Mexico, all of CO flights from LAX are to thier elite-heavy hubs, IAH, EWR and CLE - where even if you are a Platinum on a high fare ticket, you are still battling reward tickets, upgrade mileage redemptions, higher fare Plats and paid FC seats (which have become much more common with the $1,000 transcon FC "Z" fare).

A very tough upgrade indeed.

I think most Plats will agree that the UG % was around 85-90% last year and that this year, depending on your home base, has dropped to 50%-70%.

Sounds like you have good thing going.........