Why the price would be lower? Presumably the price was already agreed upon. Having a provision in the contract that the price is reduced if this argument is made to the antitrust authorities makes no sense.
I now realized that I recently saw some old tweets from this guy where he first opposed this merger and then celebrated the cancellation of the deal. So it seems he's just grasping at straws to look less like an idiot.
If the buyer is publicly listed, they have to consider their own share price,that is - the perception of their shareholders. The buyer will be punished for overpaying for a company circling the drain, they will also be punished from waling away from purchasing a seemingly healthy company at a good price.
The buyer and purchaser have to agree on which of the 2 options they publicly present to their shareholders and regulators - Amazon wouldn't be fooled because they had access to the financials and had its own judgement on viability (which may not be material Amazon's plans). However, the approach would decide the corresponding offer, and typically wouldn't be a retrospective decision, but would lock-in the higher or lower from the start.
I now realized that I recently saw some old tweets from this guy where he first opposed this merger and then celebrated the cancellation of the deal. So it seems he's just grasping at straws to look less like an idiot.