Rich, I respectfully disagree..... and you can physically prove your statement is incorrect for yourself by traveling an accurately measured path using different logging intervals. Perfectly straight paths don't seem to exist in the real world.
Yes, trackpoint interval set to 1/sec will produce the most accurate "path traveled" curvature or shape wise, but the length of the track, or distance traveled, will always be longer than "actual distance traveled".
Accuracy better for shape yes, but not for distance.
When logging interval is set to 1/sec, absolutely every bit of GPS error is added to length which results in "over distance" being reported. Most points possible being logged results in largest error. Arguably,"auto" method, and interval of "most often" produces the "most accurate overall results". (Best compromise)
That may be, but once per second works well for me, and seems to give the best elevation gain accuracy too, as it forces an elevation reading every second as well.