Jarethan, you're talking about 2 different things.
As HH says, creative team royalties often go up after the show reaches 110% recoupment. In real-world comparisons, it's like a bonus.
When a show is doing badly and losing money, the authors/creative team/service providers will sometimes be asked to waive their royalties/fees to get the breakeven down, in the hope that business can pick up. I've never heard of a show doing it post-recoupment, but perhaps HH knows more. The Prom is one recent show that went on waivers; a long-running hit show like Chicago is almost certainly NOT one of those.