or cash can be spent.
AA miles???
Kind of beating the dead horse, but if the OP maximized his cash back, he could get at least $3,500 cash back (out of 100k spend) which he could use to up-fare his economy tickets for at least 3 or 4 trips and don't have to play the upgrade gamble.
I know up-fare presents a challenge for reimbursable expenses in case of change of travel plans but for the most part there are always workarounds.