Thanks for request! Have you tried the Piano Adventures Player app to enhance your teaching toolkit? We like to call it "serious fun in the palm of your hand", for how it stylishly and unobtrusively motivates. One of its many features that you can enable is its "Wait for Note" mode--if the student plays an incorrect note, the accompaniment will pause until they correct it. I like it better than waiting until the end to provide a score or grade because it provides instant corrective feedback.