Friends with Benefits?

I've only been in a couple of long term relationships, and decided to go FWB route with someone I just met. This person is also recently out of a LTR to. We've only hooked up a few times, but each time has included alot of getting to know you deep questions and life talks. Is this normal? Do you call only for or can you call for dinner or hang out? How can you tell if they might change from FWB to wanting a relationship? What happens if your feelings change? Help!