my agent aways gets 50% of production costs on all jobs over 10k, i dont think we have ever had a problem with that. i would get worried if they wouldnt, as it might indicate a bad payer. it also means we pay lower paid crew like assistants, makeup, set builders etc early, so everyone stays happy. this is in New Zealand, so i dont know how things may work there.
TV comersals over here always get a 1/3 up front, 1/3 when the comersal is completed, and final 1/3 at the following month.
paul
www.pauljonesimages.com