Originally Posted by
Al1943
Yes they do. The "short" housing found just before the rear derailleur is pre-cut to a specific length.
I incorrectly said "small" housing in my previous post. Now corrected.
You could say the same for the rest of the housing in that package. And to quote you said the "proper length", which cannot be true for every single bike out there.
Shimano kits will come with rear derailleur loops almost always shorter than optimal length and the campy rear derailleurs are more tolerant of too short rear housing loop.