The track record feature specifies two termini: start (the first point that defines the track) and end (the last point that defines the track). Start = that point where you first press the R (record) button, and end = that point where you press the R (record) button next.
When you use the track record feature to follow a recorded track, you must specify whether you want to follow the track back to its first point (track to start) or to its last point (track to end). If you are off the the recorded track when you press track to start or track to end, i-Pilot will return to the closest point on the track and then follow the track in the specified direction. I haven't thought about, or tried, to record a circular track and then see how i-Pilot performed under those circumstances. It might be a good way to get dizzy!