We had some discussion on this in the what did you learn from your coffee brew method thread, I think...Is that pretty standard for you? lately I’ve been sticking to 5 equal pours. I’m sure it’s not absolutely maxing out the quality of every cup, but it’s been consistently good.
I am using variations on the 40:60 method. Because I am making so little, the difference between 40% and total is only 100g. So the short answer is that I only split that into two for practical reasons. Remember, the more pours you do, the more agitation you create and therefor the higher the extraction. I sometimes do 4 pours when I am having a larger serving, but usually the extra extraction is unwanted. It's another tool once you are at a grind setting that can't be further optimised.