Just tried the way point option for the first time.
It worked perfectly.

My question is, when I save it and use it again on a later day, is the 'start point' saved into the location?
For example, if I take off a few miles away from where I originally saved the waypoint, what happens if I accidentally use the 'saved' waypoint?

Thanks.

The first way point is a GPS location.  All of them are.  There's no start point.  The start point is wherever you set your AC down.  So you might think your AC would try to fly to the first waypoint, but what would likely happen is you'd get an error telling you the first waypoint is too far away.