If they made more in 2020 there is now way they can use the provision. The system and the law will not allow. Remember, the provision it is designed for the people who lost earned income in 2020 and because that income might be too low the earned income credit is reduced. If they made more in 2020 than in 2019 it means the pandemic did not affect them, that is why they can not used the provision. Hope this helps. Line C in the EITC worksheet says exactly that.