Hei Peter
one of the problems when working digitally is that the dbFs scale will give you no reference about how loud a sound is and if your signal is too hot, clipping, it will not be compressed and distorted in a harmonically way,like it would happen on tape, but because you are running out of 0 and 1 to process the signal it will sound very ugly.
Long story short: limiters are, in my opinion should only be, used to avoid clipping; to compress a (partsofa)signal in it s output where it s qua dynamics to hot for the reason of the above mentioned effect.
If you have a limiter on your masterbus, you are probably mixing music and participating on the beloved loudness war of ourdays music industry.
Mixing for film/tv is dependend on calibrated speakers, by mixing via those folks you get a close to reality impression on how loud your will be in the theater. Some tv stations have their own leveling requirements, and there are especially differences between different nations. But, just as radio stations do it with help of a VU meter, most of them mostly re-level them quite a bit.
So calibrate your speakers, dB meters are very cheap and even smartphone apps do their job quite well, and try to keep the limiter out of your masterbus. When your master is clipping better try to get rid of the problem earlier in your signal chain
p.s. also check these
http://vimeo.com/22735507
http://socialsounddesign.com/questions/618/tv-broadcast-levels