Hi Tim
I've met Tom, he's a very genial and well travelled chap. Written some interesting books* and done some tough jobs in inhospitible places. He's also lived briefly in Snorbens so after we met in the Cape the following year we had breakfast in Snorbens when he was paying a flying visit.
But, despite reading his blog posts** about his scoring system I don't understand how it works, and to be frank. I don't care,. I also have no idea about WA or WS or how they differ. But Tom will answer you if you email him, his email is on his page here
http://vinoexpressions.com/about-wine-and-work/*In Rivers of Change: Trailing the Waterways of Lewis and Clark he bouht a camper and followed the Missouri all the way to the coast travelling and alongside the river, on the river and under the rive, meeting locals, dam opereators and more, very readable.
in The Deep Sand of Damaraland - A Journal of Namibia he tells of his time drilling for water and how that affected the tribes there.
and Vino Voices: Wine, Work, Life was how I first got to meet him when he asked to interview me for the book

**http://vinoexpressions.com/2015/03/11/new-wine-scoring-system/