He is maybe just a gentleman, or a bit weak, in that he has agreed for Spurs to negiotiate with a top club abroad first, I am sure the figures involved will be alot lower than if United had gone in properly for him anyway.
There is also the arguement that no Premiership club will go for him at the figures quoted, knowing they can just wait 12 months and get him for free. City don't need him, we can't afford him, Arsenal can't afford/don't need him, he is very unlikely to go to Chelsea, so it could just be that Bayern are the only ones who will actually pay top money for him now, the rest will just wait until next year.
I sense a reluctance for him wanting to go to Bayern, and the talk of him signing a new deal if Spurs have a great season, is not only very unlikely to happen given it's Spurs, but probably just lip service for the fans anyway.