Got the same question...seems to be a bit different for me too.
On ios9 i used to get a pop up notification "xx minutes to home" (or "xx minutes to work" in the morning) when connected to my car's bluetooth fm transmitter. I don't get these anymore.
I've added the maps destinations widget, and that is showing "xx minutes to home" when I'm at work, but it's not saying "xx minutes to work" in the morning...
I've never payed attention to what was in the Frequent Locations History, but currently it says both for work and home "1 location first recorded 20/09/2016". Yesterday it said the same thing but on 19/09/2016 (I've updated to ios10 on launch day, so I would think 5 workdays/visits should be recorded)
Weird...