Ok, I think I know what may be happening, but just want to confirm a few more things.
EDIT: Looking at @michaelahess 's post here, in particular the screenshot, I think it answers my question below.
With the latest code, are most of the attributes along the right hand side of the Device Edit page for one of your units showing as Celsius? i.e. ~15-30 degrees. So things like the set points / temperature, room temperature, min's and max's, etc. And do you remember whether, before I made the most recent fix to remove the conversion, whether these were showing correctly in Fahrenheit, and it was only when you tried to adjust a set point and key in 68 that the set point was saved as 310?
What I think is the issue is that when data comes back from Kumo it is coming back in Celsius, which we want to convert to Fahrenheit where that is the temperature scale set on the HE hub. The code I stripped out recently would do that conversion if it was needed. I suspect the issue is that I need to detect when a value has been provided by a user in Fahrenheit, and not apply that conversion, which I think I may have been doing. I'll take a look at it over the weekend. If you can work with Celsius for now that would be good.... Maybe this could be the start of converting the US to metric? 
