In my experience with Irrops, it takes 24 hours or so for the upgrade instruments to drop back into my account - presumably this occurs after their once daily sweep of unused coupons, etc. This is really annoying, as I often didn't have enough e-500s left to upgrade the flight. I learned after having to sit in the back a few times to use miles to upgrade, then call MP after the flight and get the miles back in exchange for the e-500s. Note this only works if you had already cleared with 500s on the flight you didn't take

The other workaround is to get rebooked into F, but its pretty awkward to ask an agent to do that