[Herk]

Many years ago, I worked in a very small town in northern Idaho. There was a lawyer's house on a hill and his sewer ran down at nearly a 45 degree angle. It would plug constantly about halfway down. No obstructions or breaks or anything. Always fun dragging the snake 'way down the hill and running extension cords to get to that middle cleanout.

My vote would be, yes, the liquids can run away from the solids. I've always considered it better to run at normal grade, offset 45 degrees, then go back to normal grade than to try to grade the entire line by splitting the difference.