Could you add the system variables cpQuizInfoPointsscored and cpInfoPercentage in a text container to the first slide and time it for the rest of the project? Just see if it gets a value somewhere or is strange from the start.
BTW: I have a matching custom question, with partial scoring, using ListArea widget. It is on my laptop (has 5.5 still installed) and if you want me to send you the file, just send me a mail address by Private message.
Probably will blog about it, and perhaps also create one with InfoSemantics Drag&Drop as well.
Lilybiri