Feds have a "pecking order" I will use Kato as an example. He is a main eventer in RWA, was a main event in DCW and so on, when he worked at IWC he was in the opener most times. This is a general rule. When you main event somewhere you most likely either have worked your way into this position or did something else that the promoter likes you. If you have just come into a company new but have been around a while they will still make you work your way up the ladder and have opening to mid card bouts. hope this makes sense.