Once you have created a complete document, full of parametized questions, you can regenerate the whole thing at the push of a button.
Just push to button to get a completely new version of your document! There are just two things to remember:
1. It can take some time to regenerate a full document, particularly something like an exam. Push the button and go and get a cup of coffee!
2. Once regeneration is complete, check it. Make sure that all the results are to your liking. If it is mostly OK, just regenerate the questions you do not like.