Gifted and average students who aren’t given attention become poor performers quickly.

Gifted students especially.

Students who learn ahead don’t want to be told: “ok you have the material, so I’ll ignore you for a bit.” They want more. They want their questions answered, even if the questions aren’t part of the lesson plan.

Nobody wants to be told “we aren’t studying that today.”

You really can’t starve the rest of the class to cater to poor performers.