Originally Posted by
Buffaloflyer
It is true that it shows an "O" bucket however if you look at the bottom of the table they have a legend which reads as such
"(*) O: First Class Award I: Business Class Award X: Economy Class Award"
They are designating the letter O as 1st class awards available for mileage booking.
Correct. US uses the "O" booking code for preferred first class upgrades - not sure if this "O" booking class will accurately match up with that or not.
From what
dstan was able to see, it appears to be spot on for Mileage saver awards though.