Consider a multiple choice question with 2 choices. We would like Choice 1 to count for 50% and Choice 2 to count for 100%. This is possible because these grades are available in the drop-down list. Now consider a multiple choice question with 3 choices. We would like Choice 1 to count for 33.33333%, choice 2 for 66.66667% and choice 3 for 100%. This is also possible because these grades are available in the drop-down list. And so on.
This scoring scheme is possible for questions comprising 2, 3, 4, 5, 6 and 10 choices. But it is not possible for questions comprising 7, 8 and 9 questions because the choices lack grades in the drop-down list. For example, for a question with 7 choices, the drop-down list gives 14.28571%, but not 28.57143 %, etc.
If the missing values shown in the table above are not available, I should tell Kurban Rakhmanov (see that his scoring scheme is not possible, not because his quiz has subscores but because multiple choice questions lack grades for the choices.
Comments are welcome, especially from the developers.