I was just on the OpenEVSE forum and it looks like the temp gauge on the app is showing the evse temps which coincidently match the battery's temp the few time I've compared it. So I will only use the service menu battery temp in the future.
Edit: Next Day (Jan 06, 7:29AM)
This morning outdoor temperatures were -9.5c and battery temp +11c and App showed the Evse at +4c