Thanks for going through that but I think we have a misunderstanding. Some books don't work properly or at least consistently. Bribery for Beginner's for example won't give the Pchar the bonus unless the Treasurer slot is vacant. It will work only by giving the book to the treasurer. Other books don't seem to have this problem.
That was actually the first book I bought and so got the impression all books worked that way. But now I'm quite convinced there is a bug with that particular book and possible some others. Or perhaps it was a consequence of some condition or interaction I have yet to work out.