Tesla might have figured out a way to deliver faster in TX now that they got a factory here, earlier there were theories like the cars from Austin plant need to be shipped out of the state and then bring them back in, stupid theory but it was based on old rules that favor dealers. Well, back in 2012, dealers had a point, if Tesla fails as a company, closes shops and disappears from everywhere, dealers will still be there to service, repair the cars. Well, Tesla proved them wrong, Tesla is too strong now, old rules are bound to be twisted.
I believe they are not waiting for the payment anymore for shipping, it gets complicated and may cause unnecessary delays. They can probably ship to local service centers whenever, which could be legal and switch the ownership once customer is done with online payment.