Jungle S Ranks

Is it just me or is it really difficult to get an S rank on a junglers who typically top lane? In my personal experience this would include Malphite, Trundle, Nautilus, Jax, and Maokai. It just seems really hard to get an S on them, but I go top lane with them and boom S rank. I am thinking that the top lane increased CS numbers are effecting getting S ranks on typically top lane junglers.