Huh, I would have ruled it a single head with two cutting surfaces, just like having a double edged sword.  Basically its a martial version of a double-bitted axehead, which is a single piece of metal.  I think I might have one of those in my shed.  Doesn't matter anymore anyway, I've gotten rid of that and changed his weapon selection a little bit.  I'll update his sheet in a minute.  Honestly, the advantage of that weapon doesn't make a whole lot of sense anyway, mostly because it should also be applied to most larger swords and greataxes (since its how most of those are drawn anyway.)