Interesting approach....
In your first post you said
"
Here's the spiel I used to give when I was teaching math or eng at the start of the class: 'I get paid the same if you all get As or Fs, or any combo in between. the school will still cash your tuition check no matter if you pass, or fail. There is no grading on a curve, there are no fancy adjustments, or interpolations of the raw data. You will be presented with the material, it will be reinforced by homework, you will be tested, and your grade will accurately reflect your retention of the material over the semester. Please bring your drop class slip to me for signing.' Most of my classes were very well attended "
I am just a poor ol commercial contractor building multi million dollar, very complex structures.... If I accidently leave out a critical beam /column and the building collapses... Do I get credit for the part that still stays standing..

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My point is, either the task,( for me) or the test ( for the student) conclusion is right or wrong....
In the real life, you don't get credit for partially successful outcomes... Why give students that option ?
Thanks in advance for your answer sir...