This was sent in by a reader who really is digging through the new previews from Forgeworld. I had not seen this yet, and while it may mean nothing, its the first time we have seen some sort of percentages listed for in these products.
Please remember that we are discussing the possible rumors of percentages appearing in some form or another (most likely not like Fantasy), in Warhammer 40k.
via a reader here on Faeit 212
Dunno if you will get this or if it helps but check out forgeworlds new products and have a look at the books and it will give you teaser pages, well the page with the force organisation on has something along the lines of a lord of war leviathan and if you read it's blurb it references about percentage, this has probably been picked up before but thought I would let you know.
I went and looked what is said from the previews of the Legiones Astartes Campaign Armylist Preview on the Forgeworld Site: Here it is.
Unlike usual Lords of War, this may represent any percentage of your army value (and indeed constitute your entire force in a single model if you are so inclined, brave enough and your opponent agrees) in contrary to the usual rules of Warhammer 40,000 this Leviathan is both your Warlord effectively (and uses its own special warlord unit listed) and is also a scoring unit.