Yesterday did a 109 miles ride and when reviewing the ride info from the Garmin 705 computer I do see discrepancies in elevation gain.

WKO+ : 9266 ft.
Traningpeaks.com : 8999 ft.
Garmin Connect : 9745 ft.

Everything else is pretty much correct, distance, time etc.

Is Garmin website correct? Why would trainingpeaks.com or WKO+ was so much different?