Unfortunately there's no exposed edges. The tile itself (12" x 24") is a little over a quarter inch thick. But the total install thickness is about half an inch. It's my impression that the mortar thickness itself should end up being about a quarter inch, but they claim they used just a really thin layer. Last pic is a tile on top of quarter inch (exact) piece of trim.
I'm not asking if they should have used it or not, just that if they didn't, I don't want to be charged the extra $500 or so. Is it possible they did actually? Is quarter inch hardiboard actually quarter inch thick?