Hotfire
the term "Superior Proposal" is mentioned 59 times through the Acquistion Scheme Booklet.
Regardless of whether it is simply boilerplate (ie because the solicitors know that sometimes this happens in situations like this) or something more deliberate .... there is a chance (pick a number between 1 & 100) of a better offer.
My guess is that some are playing this possibility and assigning a premium to TXN over SEA.