A reproduction is essentially an exact copy of the same work while a derivative work is a different work but created by copying some aspects of the original work.
Reproduction is narrower than copy.
But is that income generated from the copyright or is it from other unrelated sources. The deprivation of income comes from failure of the users to connect to the service Westlaw provides its on-line users, not in their creation of the derivative work that is the modified software. I don't think so but others may disagree. And of course, under current law the licence is probably not binding, but under the new 2B it is.