I see what you are saying but it does not make sense that a cable 'shortens' or 'shrinks'. By 'tightens ' I mean the diameter decreases. Overall length increases 'a bit'. Due to geometry of coil winding, all coils with abutting winds (like our flex shafts) will have an overall length increase when 'wound' beyond their initial coiling. You may not be able to see it if coil is stiff, but if you can wind it, in general, the overall length will increase.
You would always want to run the coil in a 'winding' direction so that it maintains the same or narrower diameter in the tube. When run in a 'winding' direction, the cable lengthens. Here is a diagram showing what I am describing.
If you 'wind' up the cable, it actually lengthens a bit. Therefore, I always make my thrust washer snug to tube bushing. Never had an issue with washer wear, BB or plastic. You can test this by winding a wire around a tube diameter 'x', slide the tube out, and then twist the SAME length of wire around a smaller diameter tube than original 'x'. The smaller wind diameter for given length of wire has an overall longer length of the coil. Same principle when 'tightening' the wind of our flex shafts.