I checked, and the cilmb and distance are roughly 5% difference, although it's not intuitive that it only takes ~16-17 miles for that to round to a mile!
For readers not in our text chain, it looks like my fenix was pinging at 1-2 seconds, while I see Barbara's record rate ranging from 1-2 seconds up to 10s (just checking first few rows). Maybe hers is in some smarter mode?
When I had my 305 in smart mode or five second mode (I forget) mountain biking at Highland, I came up two miles short of the published odometer-based distance (also around 16 miles nominal), and given our brush bashing, that might do the trick. So.....much....brush. Arms screamed during shower.
Then as I joke I thought, well I punched the flags! And then realized that 25 flags * 100 ft * 2 (out and back) would yield a mile, except we never parked anyone to punch.