300 feet is close to noise. I suspect steeper/longer climbs make the number more accurate.

Hopefully, cyclists aren't too concerned about logging 300 foot rides.

RWGPS and others use the same elevation database. The resolution of that database is fairly low, which means it can miss climbs that cyclists care about. That is, the database numbers will tend to be lower than the real number.

It seems many people think it's as accurate as horizontal distance. It isn't.