If you think that's steep, don't look up what a Moen Flo or Phyn Plus will set you back 
Apparently, doing this type of measurement reliably, well, and safely isn't cheap.
I've had Flume in-place for 5+ years (I use it with a battery-conversion kit so that it's now mains-powered), and it's been great - I've had no issues. I use Tom's community integration.
My plumber offered a Phyn Plus at (his) cost w/ free install when he was doing some other work on my main line a couple years ago, so I have that too... That needs HA to get into HE, but it's been issue-free as well -- and it's got some pretty sweet features.
Belkin recently bought Phyn from Uponor, and I'm admittedly skeptical about whatever future plans Belkin may have, but we'll see -- that sort of thing is (unfortunately) somewhat inevitable. The Phyn doesn't use an impeller, so if it does brick someday, at least I don't have to worry about any parts breaking down in the pipe.
