[ordu]

> Shouldnt the costs for sales and marketing, management layers, store janitors, etc. also be included in variable capitol...

I do not know whether they should or not. I'm not an economist, I tried to read some textbooks at some point, but finished not a one. I've decided to read article because I was interested how it is going to deal with the costs of R&D. I had no clear idea how to do it. And with first read-through I missed the quoted excerpt, so I though that it should be a part of a variable capital, though I was surprised it was not mentioned in the article. I reread article and found the statement that R&D costs should be ignored.