I don't really know any details of how Iced Earth finances are broken down, and even if I did, I wouldn't repeat them here. However, I can post some quotes from Jon Schaffer interviews that may be instructive. Note that these are from ~2002, so things certainly could have changed over the years:
"I've worked with Matt and coached him through every single thing. Matt doesn't have the kind of personality that he would have done this if it wouldn't have been with someone behind him....As far as that goes, everybody is replaceable including Matt and he knows that. Does that mean I'm going to fire him next week? No, as long as he does a good job and works hard and is dedicated while doing the right things, then he's in. We have a very good relationship, he feels fortunate to be here. He knows it wouldn't be if it weren't for me. It's become a vehicle that he can do things he enjoys to do. He's a performer not a songwriter."
"Everybody in ICED EARTH is on contract. Nobody is a member or a "percentage owner" of the company, it doesn't work like that. As long as these guys work hard and stay focused and do their parts, I don't ask much… well, actually, I do ask a lot. I ask of 100% of all of them. Show up, do you parts, do your job, be reliable, and no drinking before the show, none of that kind of shit. Everything else is pretty cool. Then they have the vehicle to go out and play music in front of huge crowds and make money at something they always dreamed of doing. If they fuck up and cross that line to where it costs me money, causes headaches and problems, then we have problems. I think at this point though I've got a group of guys that have been around long enough that know this is a great opportunity for them."
"Well, I asked Larry to leave the band. There's not really a lot of space for lead guitarist in ICED EARTH, he doesn't really have a job to do. You know, solos is all that any lead guitarist in the band has ever done, and I record all other guitar parts.....I thought it would just be better for Larry, because with the involvement that he had, there's no guarantee for a good future for him in the band. So I said, 'Dude, it's better for you to just concentrate, go to school, get a career, forget about the music business.' He's just not made for it....Larry was a good guitarist, but creatively he didn't bring anything to the table. He did come up with a few cool solos, but that's it, and solos are not that important. You can't even copyright a guitar solo, it's not like you're gonna make a bunch of money playing guitar solos. You have to write songs."