I emailed fi tech about a two step and they said no. They also said they were working on a Mean Street edition that they were working on that would work with a two step and to watch when it hits the market. Well it has.
So I called them to confirm if it would work with a two step and the man there (Cody was his name) said that's not true they will all work with a two step as long as you don't ues the FI timing function