And changing the powerdown to 24 hours for what reason?
After centralizing the chain so totally and all of the dapps shutting down in protest, it would otherwise take weeks for every single user to rush to the exits as fast as possible and the price of STEEM to tank to zero. This way, the dumping can commence the day after they unilaterally change monetary/issuance policy of their centrally-managed, centrally-issued, unregistered publicly traded security.
I think it's more likely that they had to agree on doing this in order to have the exchanges move along with powering up all of their user's STEEM.
They knew that as soon as the SP on the exchanges was used to give back voting rights to the Steemit Inc accounts, those in turn can implement the new fork and they wouldn't need to use the tokens on those exchanges for voting anymore.
So the power down is likely added to allow the exchanges to power down quickly again once everything is "back in order", so that their users won't be too mad.