Garmin Golf App vs E6 distance differences?

I have been very happy with my R10 but am curious if there is difference in software/readings with Garmin Golf App vs E6 Connect. Garmin app is spot on for my numbers on range but when I use E6 on range (range vs course for a flat baseline) I am a full club to a club and a half longer than I actually am. Anyone else having this issue with E6 being long, if so any recommendations for settings for a fix?