An update on this old thread:
I used to think that JPI changed their software at some point, to increase the amount of data which could be stored, and they did it by storing data only when it changes by at least 5F. This manifests itself in the large steps in the stored data:
JPI never replied when I asked them on multiple occassions. However a check of old EDM700 logs (from 2002) shows that the logged data is always at least 5F between consecutive samples, so nothing has been changed there
I cannot find a config for the data log resolution. There is a config for the display resolution.