I need help understanding how the Canvas grade book decides which grade to include for a classic quiz with multiple attempts and a late penalty associated with it. 

I have a classic quiz with 2 attempts, which is supposed to take the highest score. I also allow students to turn in these quizzes late with a 1% deduction/hour late. 

If a student takes an attempt before the due date and scores 28/30 for the first attempt and then takes a second attempt after the due date gets a raw score of 30/30. However, after the late penalty is incorporated into that second score, their grade is 20/30. For some reason, Canvas automatically takes the second score, even though it is lower. I am pretty sure it automatically incorporates the late penalty to any submission, even one submitted before the due date.

This does not make any sense. Why can't Canvas change the grade book to simply take the highest attempt score after considering the late penalty? Every other grade book I have dealt with does this. I teach huge classes, and I can’t manually monitor this issue. My only solution is not to allow late assignments. 

Plus, I would love for students to be able to practice the quizzes before exams without any penalty. However, this is also not possible with Canvas.

Is this issue going to be fixed? Because this grading policy honestly does not make any sense.

Thank you