I've seen that patrol grid assignment file once. It's scary. It's odd the game doesn't just give you a random patrol on its own given how poor the stock patrol file is.
I could quite easily write something to redo all flotillas and patrol groups much as I did with convoys.
I just need the meta information of which, where to, and when for each.
And, yes, the patrol grid is definitely something you notice, even if no one ever mentioned it. I haven't done an IX, ever, so I never noticed the ones already done, but I do notice when I get strange patrol grids (no Arctic for 11th in '43?).