Here I don't agree. In a quiz, to collect points is necessary to pass the exam, so points are the only reward possible.
In a lesson, instead, where answer should ask for reasoning and not for memorization, to see to have given the right answer is the most relevant reward. Grades can give more reward, of course (but only if mechanism is very very simple to understand for the student: the best thng is simply to tell him: "ten points for you if your next answer is right), but I think (and saw working on some 100.000 students - I am really a bit old) that the right answer is really a very good reward. I think that the best mix is: if your answer is right on first attempt you win some points, otherwise I give you an help (the comment), you return to same page and try again and you have the reward to see that this time the answer is right (but no points. I don't need to distinguish second attempt from third: if pupil doesn't give right answer at second attempt, having had an help too, that means simply that *I* was not able to explain myself).
In a lesson, I would use the grading mainly to suggest the student to go on with the next activity or to repeat the lesson (I'll open soon a new thread on grading and linking).
Of course, there are many tricks to make your module do what I want. I can, for example, put the Number of Attempts to 1 and turn the wrong anwer to a new page really identical to the "same page", or I can extablish an higher grade as threshold...
But the actual mechanism of grading seems me too complex for a good didactic strategy. I don't know if it can be easily changed and it is very amusing to criticize other people's (very good) work...
...but I think that the grading mechanism is the only thing that is not perfectly tuned.
If i can collaborate in some manner (I know less than 10 instructions in php, it is not a great knowledge...) I will do.