Garmin R50

I got my R50 in yesterday. Started with driving range mode just to get a feel for it. Hit about 25-30 shots with an 8 iron. My normal yardage would be 160ish and I had consistent flights of 105-110 which is way off my norms. I hit on the range and launch monitors often and know my yardages fairly close. Any idea why its so different? What can I do to get it right?