Multiple choice question advanced options not saving

I have a teacher with unusual setup for lesson questions. She wants Multiple choice question to score 1 point for each selected correct answer. Selected wrong answers are to be ignored (they get 0 points if they are chosen and the same 0 points if not chosen) This is a strange way to score, but plausible, I guess. The problem is, when she uses advanced options of Multiple choice question to set the score of the alternative to 0 if chosen and 0 if not chosen, this settings are not saved. The settings revert to either -1 is chosen or 1 if not chosen. the global setting for Multiple choice question is "Give one point for each incorrect option that haven't been chosen" if the global setting is set to "Give minus one point for incorrect answers", the settings can be saved, but test often (almost always) results in error "InvalidArgumentException: Value must be less than or equal to 'raw' (-1) [0] in TinCan\Score->setMin() (line 150 of []sites/all/libraries/TinCanPHP/src/Score.php)." First of all, I think this is a mistake to have Multiple choice question setup as a global setting. There can be a default, but there should be a possibility to choose scoring method for each lesson that uses Multiple choice questions. Second, how can I properly implement the "no penalty for wrong answers" approach?