If only it were so simple. When you purchase a revenue ticket you buy not only air transportation, but also a discount on future travel. You did not redeem only 12,500 miles, but also the miles you would have earned on the paid ticket. These might include:[/LIST]
I agree there are a lot of adjustments you have to make for sure. I guess it is better to say that my flight cost me 14,500 miles if you include the loss of 2000 flight miles. (Actually I booked for someone else who doesn't have a FF account, so I didn't lose 2000 miles there.)
For a lot of us, MQM have zero value since we'll never revenue fly that much on one airline in one year. And even if we do, we'd have to fly again on it to get the benefit. But for a tiny minority, status is easily worth several thousand.
Another adjustment is that miles are tax free, but pleasure travel has to be paid with after tax money.
As a general formula though, I think just posting the info in my example format will yield more useful information for app o ramas than anecdotes by bloggers about extremely high valuations.