In cabling, when setting an overall length, if a cable is already fixed to multiple locations, creo has a hard time regenerating and actually creating the overall length you desire. I think it has to do with how it's adding the lenght to the cable segments, I believe it tries to add the extra length divided equally to all segments betwen locations.
If you could pick two locations where the extra length is added between that may help the program generate the cable easier, and also in reality, you'd want to be putting the slack in a specific location anyway.
