YM and ES are correlated, not duplicative. YM on any given day will move 4 to 12 YM pts for 1 ES pt. So in your example 5 YM = 1 ES is well within the norm.
YM and ES are correlated, not duplicative. YM on any given day will move 4 to 12 YM pts for 1 ES pt. So in your example 9 YM = 1 ES is well within the norm.