He's just applying logic to the situation, just like he did with Martinez doesn't mean he has inside knowledge or anything.
We will accept a bid at some point, be that £18m or £24m or £30m. United know we will they've done it before with Rooney, they know Kenwright's words have no backing. They're also in a unique position because Moyes knows what would tempt the board it's just up to them to hit that number. Then it'll come down to Baines, United can offer him what ever he wants money wise and CL football and trophies. So to me it's all down to Baines because they have the money to spend if they really wanted to and it'll be up to him.