I had this issue; my LR said 100% was 280 miles. I found hanging out for a week or two in 20%-50% battery range (charging only to 50%) and then finally charging to 100% (be sure to let it continue charging at 100% until it says "Charging Complete" This seemed to have recalibrated the battery and I had 305 miles at 100% again.
For me this worked when a 100%-5%-100% run did not.