Join Date: Dec 2004
Location: Ireland, UnderH20, AUA, Brooklyn
Programs: Delta Charter KM, DM180, RW, DM, SC, SkyBonus; HH Diamond, IHG Plt Amb, Global Ent, TWIC
Posts: 2,191
Expertflyer doesn't show, as far as I know, award buckets but just upgrade buckets, i.e. V and G for domestic as well as X and Z for international.
If Z is available you can use miles (or PMUs) but you need an upgradeable paid ticket in the first place.
Though we are supposed to be able to upgrade award tickets soon but not sure what bucket those will come out of.