Originally Posted by ffgap

A question of my own: I tried to upgrade Y -> J on a LH flight using 3 evouchers which showed outright availability for miles on the M&M web site. The flight in question is LH400 and again, there was business award/business flex award inventory open.

I have heard before that I award and I upgrade award space is not 100% the same. But I've also heard that Expertflyer stopped listing M&M inventories. Is there any way I can find out if there is space prior to booking? Was somewhat surprised yesterday when the call center told me: "Waitlist only."