Originally Posted by
xliioper
Pay with Miles tickets are just revenue fares that are partially/wholly paid with miles exchanged at 1 CPM. I doubt they would be lower than Award fares or Miles + Cash awards (which are just Award fares, but where redeemed miles are partially paid for with cash at about 1.8CPM). I suspect you are making too much out of the order of listing types of tickets which are eligible for upgrades. Delta has never really exposed in detail how "Fare Class Groupings" work with the various ticket types.
I've always understood pay-with-miles tickets to be regular fares for which payment is split between money and miles (at one cent per mile) or paid totally with miles (at approximately one cent per mile). I don't think DL categorizes them as award tickets at all.
Isn't there some other option with a similar name in which you use miles for only some segments of a ticket? IIRC that's the one that gets low priority. This one appears to be called Miles + Cash, but I've never fully understood how it words, nor have I ever considered using it. This would seem to make sense only if you're short some miles for an award ticket you want, as you're effectively buying the needed miles from DL as part of a single transaction. I guess it avoids the problem of buying (or transferring) miles only to discover that the award ticket you wan't isn't available any more.