How did the scousers manage to persuade (con) Sunderland into thinking that N'Gog is worth �7 Million?

Sunderland are desperate now. Gyan is injury prone and Bent is gone. They've no quality strikers although I seriously doubt N'GOG is quality, they're looking for the 'cheapest option' and really are willing to pay anything under 16 million to get a striker. A shite one at that.