I found the piste:grooming description from the 'Piste maps' or the
Key:piste:grooming pages that was derived from the earlier not very
clear. I've made an attempt to re-write it to document actual usage
I'd like to have some comments if you think I missed something.
This is about actual usage and better comprehension. If
the values re-used from one type of piste to another does not
suits you, it's another story that can be dealt with later.