User blog comment:Zilla4444/AP Version of Black Cleaver/@comment-4915885-20120611225649/@comment-5009341-20120612183004

^^

'the 5% cdr is for better calculating what items u get for max cdr, most aps pick 4 points in sorcery and have 4% cdr at lvl1, and usually take 2 15% cdr items (dfg+athene), so that they have 34% cdr, but there is no 20 % cdr item (nashor doesnt count for real aps), so they have to get a 5% cdr item, or get cdr runes (what noone except me does like it seems)'