User blog comment:Jimeee/Skyrim 1.9 beta update adds Legendary difficulty and raises level cap (Updated Apr 8th)/@comment-4897726-20130304205056/@comment-71.188.236.207-20130305011000

im pretty sure you can only upgrade each skill once, reread it in a different context, it says to legendary, if you were able to do it more then once i believe they would of added adept/expert/master and so on maybe even flawless and other rankings, and if not that then they probably woulda stuck the word multiple in their somewhere, but they didnt so it leads pretty much everyone to conclude that you can only upgrade skills once.