You do realize that its not the chakara consumption but the eye back lash you get when you don't have EMS. When you don't have EMS and use MS techs it strains the eyes to a very bad point that it could almost bring you to your knees. This is A LOT different now that he has EMS. His EMS makes his MS techs normal abilities now. If that was the case then he would not be spamming Susanoo again right off the bat after he got his EMS as he is doing now.you do realize the chakra consumption of amaterasu? and incredible reach really i only saw between 8-15 meters in length tops.
Also stop dictating the reach on his Susanoo sword. Itachi has shown that his own sword has long reach. The only difference is that its not the Totsuka sword when it comes to Sasuke.