Currently when saving a new Flight Plan for the first time the default Flight Plan Name automatically becomes the "Departure Point" to "Last Waypoint" followed by a list of the intermediate "Waypoints" in order. For example: (Departure Point) to (Last Waypont) via (Waypoint#2, Waypoint#3, Waypoint#4). One can optionally edit/change the Flight Plan Name prior to saving.
Unfortunately when a Custom Locations is included In the default Flight Plan Name it is automatically listed as a number (assumed to be the Custom Location database record number) instead of the Custom Location Name. For example: (Airport Identifier) to "1". I believe this instead should be the (Airport Identifier) to (Custom Location Name)" and request that it be corrected.
See also the related Wish List item by the title Flight Plan = Default Name - All Saves.
Richard
Reference: Version 4.09