Looks like one of the problems of confusion in this thread is terminology. When miguy asked, "Will they show you the bill with us on a flat rate??" I have a feeling that it should have been worded as, "Will they show you the bill with us on a flat rate per mile?" which is different than a flat rate load.
If the .15 FSC load was, for example, a Panther van load at .77 a mile plus .15 FSC for 533 miles, it should have paid .92 per mile totaling $490.36. The FSC is an estimate, but it is usually within a penny, so if the total paid out was off by more than $5 or so, contact Driver Relations and find out why. If the load paid .77 a mile ($410.41) and nothing for FSC (or bonus or some other credit for that PRO), then someone made a mistake that should be able to be corrected.
If it's a case of, "Well, the customer didn't pay any FSC, sorry," then whoever is making the FSC "estimates" on the load offers is incompetent and needs to be made accountable. You can take the "estimate" disclaimer only just so far before it becomes a bait and switch situation. I have a feeling, not posititive, but just a feeling, that if I delivered a load to the wrong consignee, they'd make me accountable for that. There's no difference. If they'e gonna say "We pay what we say" (which is the alledged reason for the Load Receipt in the first place), then they need to pay what they say, or don't say it.
More than likely, it's a simple accounting mistake and will be corrected. If it's something else, don't meekly accept the first answer. Hold their feet to the fire, make someone accountable, get to the bottom of it, make a racket. I've found many cases where there was a problem, and Driver Relations sends it to Research, and it was quickly solved. I've also found that in too many cases the "research" consisted of all of 2 minutes of reading the notes that in the PRO, notes that were entirely incorrect, and the decision from Research is based soley on those notes.
Get to the bottom of it. Find out what happened, and why. If you can do that, whether you're right or wrong, then you will have a much greater insight into the same problem if it happens again, and will know how to best handle it.