Good thread, this is something I've had a problem with since I started using this type of approach.
The main point seems to be that GPS distance to next approach waypoint can be confusing.
The fix seems obvious: Publish both distances. Not ideal of course, but you could make use of the distance to MAPt and use the distance to next waypoint to crosscheck - this would stop any waypoint confusion.
Most GPS units are able to display total distance to each waypoint, and this page is only required until you reach the final approach fix, where the distance becomes intuitive.