This is how I like painting, I get right to the point even with the blockin.
I’ve seen many artists work the entire painting all a once. It’s a very good method but I don’t like it because I feel that I’m fighting with inaccurate painting that has just covered up all my drawing. So I try to paint as accurately as I can at the beginning. I paint thinly for the blockin, and yes I will go over the entire painting at least twice but this way I have a really accurate foundation to adjust for subsequent layers.