I would not change anything about your job until the day after you close. My husband had two jobs. He was asked to be a director at one of his jobs, so he took it even though he had worked there 5 years and was making a lot more money, just him making that change postponed our loan until they had thirty days of pay stubs. Honestly, I wish we hadn't mentioned the change at all. Then again, at the closing table they made us sign something that said that nothing had changed with our jobs or personal finances, so I wouldve had to lie--which I don't do,
It may work out if you do that, but with you bring so close, I wouldn't do it.