Project scope for a insurance broker

So we're building a web app for an insurance broker. We're about 60% done with the project, but my boss one day just told me we need to add a functionality that incorporates deductable, which is nowhere in the requirement specification. Even worse, instead of explaining what the client needs, he just told me to look up and research how deductable works, and I told him I'm not an insurance agent. Is that normal? Or i guess a better question would be is it expected of me to do my own research for anything outside of software engineering/programming?