It's really hard to create a segment with a specific distance like "last kilometer of Mouchettes mount ascension" or "1st 5 miles of Beaujolais Marathon".
You have to create your segment trying to guess the distance, then modify again and again to get closer to the exact distance. But you can only modify or create a segment 5 times / 24h, then you have to wait 24 hours. It's really hard to make a segment with an exact distance in less than 5 tries.
Just showing the distance of the segment when we move start and end point will fix that easily.