Anyone have any idea on how to get the Fenix 6x anywhere close to accurate on a treadmill. I have done several outdoor runs with GPS at 8-10 min miles for 5 or more miles. I have calibrated and saved every run on the treadmill. The treadmill run is still showing no faster that 18 min mile while in reality the runs are never slower than 10 min mile. A two hour run was over 6 miles off. I don't expect a watch to be perfect indoors but this is not even close. A Fitbit at less than $100 bucks does much better. Any ideas?