I was wondering how you save a what if grade so that when you click "Show Saved What If Scores" you see the what if grades that you inputed
The documentation in the Student Guide makes it sound like it's automatically saved for you. See the bottom of this lesson: How do I approximate my assignment scores using the What-If Grades feature? There is a similar page for the new gradebook, although it looks like the process of showing saved what-if scores is the same for the students: How do I approximate my assignment scores using the What-If Grades feature in the New Gradebook?
The explanation at the bottom of both of those lessons is:
To view your grades using any What-If scores you've ever tested in your course, click the Show Saved What-If Scores button.
If you have played with the What-if feature, you will need to revert your what-if scores to get back to your real grade. Otherwise it shows you the score you put in. It also gives you a warning that this is not your official score.
Retrieving data ...