Why? Too many of those "perfect" HW papers were spoon fed to the student by parents or tutors. Other reason, struggling students would be discouraged from even trying if they knew they'd probably get it wrong.
The result of that approach? (1)EVERY student who met my criteria passed all their tests and quizzes. And I NEVER scaled grades. (2) Class average and median grades both increased dramatically (3) Administrators sometimes got really upset that my student grades weren't a "perfect" bell curve.
My nickname in school was “Curve Killer”.
You did it as I always thought it should be done. Not that what I think matters, but it seems like the best, most logical approach.
Well done.