Casting call question?

-This is an offer I received from an industrial company:

Principal talent rate: 100.00 hour session and buyout..... What does this mean? Mainly the buyout?In the UK it would mean that the person who gets the principal role would do the session, act, and then sign away their rights to any further payment for that piece of work from the company, no matter how many times the commercial or whatever was aired.

Check, but I think that's what it would mean.