Baker is correct. Price of cost per 1 duribility repaired is based on the base item, then it gets increased higher depending on the mods it has. My Cruel Giant Thresher of Regeneration had 2 shael's in it, and 1 duribility costed 4k, and duribility ran out quickly, often within less than 3 minutes of cowing duribility would be at half. If you have enough for a "CCBQ", you should have gone for for a Fury Balrog Blade with The Grandfather so that the whirlwind speed is averages out, dealing more damage than a "CCBQ", and having more bonuses.