Sorry, I was vague. :^/ I should have said that it is my personal, non-canon interpretation that the Brothers Feanorian sat around for a while deciding what to do about Maedhros, so he spent a good deal of time in Angband, awaiting their decision. I like to keep his time dangling upon Thangorodrim to the bare minimum of five years simply because I don't like to suspend disbelief to the point where I'll believe that he survived up there for twenty or twenty-five.