It appears that other instructors have had similar issues changing the point values for questions within a quiz. I imported a quiz that was exclusively MC (totaling 100 points) and then I added a 30 point essay question. When I inserted the value of the essay. the quiz was now a total of 130 points. I wanted to change the values of the MC questions and it appeared that the only way to do this is to create a group for the MC questions or alternately changing each value individually. Had a chat and when they described the dragging of the questions to create the group, I said this is really beginning to sound cumbersome. The person offered to help and about 8-10 minutes later my new quiz appeared with the correct value assignments. And this is the length of time taken by a tech specialist. This is no way a criticism of the help person. He was wonderful.
Alternate suggestion. Create a button that allows you to assign the same point values to all questions within a specific quiz. Once having done that you then have the ability to edit the few questions requiring new point values. This seems much easier.
Look forward to people's feedback.