I will check — I think the main reason it’s done at program level is this: since multiple zones are allowed to run simultaneously, it’s generally not possible to extract the flow rate for each zone individually. In many cases, probably only one zone is running at any given time, but in the general case if zones can turn on at any arbitrary time and multiple zones can run together, it’s not possible to extract the flow data for individual zones.
We generally test the UI with Chrome and Firefox — we’ve stopped testing it with IE, because IE often lags behind on modern browser standard, making it fully compatible with IE would require us to spend more time to fix things that otherwise work perfectly in other browsers.