I am doing my first installation and I have a question about the 6 inch rule for the joints. As far as I understood I am supposed to place the edge of next plank at least 6 inches apart from the current plank's joint when we are talking about the adjacent rows. But what about the joints which are 2 or more rows apart? Is it OK for them to be,say, 2 inches apart?

In other words, is it OK to place plank #4 relative to plank #1, as shown on this picture, not lined up, but off by and inch or two and definetely less than 6 inches

yup