Yes, this is standard "good negotiating" tactics: Get the other party to commit in principle, then negotiate price.

He's both backed the board into a corner and started clearing out dissenters simultaneously, therefore they are now under pressure to sell at any reasonable price. Given the market downturn - and continued weakness going forward - this provides a movable discount he can press.

Furthermore, there is no reason why he can't claim that those "5%" bots should equal a 10-20% discount, since those bots by their nature have an outsized impact on the platform (ie. real people may only post 1 tweet per week, however most bots are voracious posters)

Frankly speaking, the "best" outcome would be for us to not have a single twitter at all, but instead transform twitter into just-another-mastodon-node