Originally Posted by
mherdeg
If UA holds back upgrade capacity, as they are wont to do, and if there is demand for more business-class upgrades than are available on the plane, as there often is, then your K fare + copay would be prioritized below all W fare + SWU requests and might never clear. By buying higher fares you're bidding against other travelers for the C seats.
Or - do not put your MP number in the record and get a TOD upsell offer. This will trump everyone on the UG list, including 1ks with Y tickets, probably at a much lower cost.