Extension of CoursePress "build page elements" possible?

CoursePress Pro offers different kinds of elements to build a page of learning units (e.g. "Text", "Image", "Video", "Multiple Choice" etc.). I need another one besides the ones offered: A single Choice type that differs from the built in one in
- randomly change order of the possible answers
- after selecting an answer immediately all other possible answers are grayed out (no longer selectable), and an explanation about the chosen answer will be shown below
That also means that for e.g. a choice of three possible answers there must be fields in the admin part to provide three different explanations.
(the reason for all this is, that we have a 10 year old hand made system, that can do all this. There are 150 single choice exercises with two or three possible answers and all explanations for all possible answers - this system should be transferred to a newer technology. The system is about German labour law - a rather specific topic, where specialists are expensive - so "redoing" all exercises is out of question)

Long explanation, short question: Should I add this new type of page build element as a new element, or should I rather modify the existing single choice element (file unit-modules/radio_input.php). The random order would be useful anyway, and if in the definitions of the course no "explanations" are given, the element works as it does now.