Originally Posted by
af fp
If there is availability for Business on CO with miles the upgrade should also be allowed.
This is not necessarily true. Upgrade and full reward seats are not necessarily the same bucket. Plus, a one-way ticket will cost a pretty penny. And the majority of the reward availability I saw was on DL, where it is not possible to redeem CO miles for an upgrade. It is a reasonable approach, but won't always work when partners get involved.