Yeah Ozzy (and Sharon) have a long history of bringing people in, having them do 90% of the writing, but getting no songwriting credits therefore taking all the money.
Lee joined Osbourne's band just before 1983's 'Bark at the Moon,' replacing late guitarist Randy Rhoads. When the album appeared, all lyrics and music were credited to Osbourne -- in direct violation of an agreement Lee says they had going into the sessions.
"I was told from the get-go, '[If] you write part of the songs, you'll get writing credit, you'll get publishing. That's part of your deal,'" Lee told Eddie Trunk in a new interview (via Blabbermouth). Later, however, after he recorded the final guitar track, "They said, 'Ah! We have the contract for you.' And in it, it says, specifically, 'Ozzy Osbourne wrote all the songs. You had nothing to do with any of the writing, you have no claim to publishing and you cannot say so publicly.'"
When he balked, he says Sharon Osbourne, Ozzy's wife and manager, told him he'd have to accept the new terms -- or else his contributions would be erased. "She says, 'Because if you don't, we'll give you a plane ticket, you go back home and you stand in line and you sue us. In the meantime, we have all your tracks, we'll get another guitar player, he'll redo your tracks, and you'll have nothing,'" Lee added.