Happy to help if I can, but I'm not entirely sure what you're trying to do. As I understand it, you want to covert a 0-24 rubric to a 10 point maximum in the gradebook, with the rubric's 16 translating to 5.5?
If so, I am surprised you're saying that multiplicator=1.35 and offset=-3.5 works. By my math, they shouldn't (24 * 1.35 - 3.5 = 28.9; and 16 * 1.35 - 3.5 = 18.1). Are you sure you're getting the right results in your tests?
To hit the points you're listing, multiplicator=0.5625 and offset=-3.5 should work. Note that this effect will go throughout the rubric. A rubric score of 0, for example, will be -3.5 in the gradebook. Is this the effect you're looking for?
If so, I am surprised you're saying that multiplicator=1.35 and offset=-3.5 works. By my math, they shouldn't (24 * 1.35 - 3.5 = 28.9; and 16 * 1.35 - 3.5 = 18.1). Are you sure you're getting the right results in your tests?
To hit the points you're listing, multiplicator=0.5625 and offset=-3.5 should work. Note that this effect will go throughout the rubric. A rubric score of 0, for example, will be -3.5 in the gradebook. Is this the effect you're looking for?