Ohh. My bad. This Exactly as you wrote. They issued bounty after fell of Kaido during celebration and when Luffy's first bounty was introduced.
Yeah. Today I'm free so I'll do it to kill my boredom. Lol
Now here's even more detailed series of events :
- Chapter 956, Revocation of Schibukai system. Coby went to Amazon Lily to capture Boa Hancock.
- Chapter 957, for the first time bounties of old yonkos were revealed. That is after schibukais were abolished and marines confirmed the revival of Rocks after continuation from chapter 956 events.
Now Brannew revealed BBs bounty is 2.247B as emperor and that is revealed when schibukais system got abolished and Coby went to Amazon Lily, now even in flashback that's when BB fought with both marines and Kuza pirates.
Now you have to believe it's either 2.247B at that time or suddenly in few hours it becomes 3.99B !?
Believe it or not but Oda revealed the boost in this way just to hype up Boa and BB fight and in flashback.
While all these new bounties of schibukais or emperors starts spreading after Luffy beat down Kaido and on the celebration day as showed in chapter 1053 when newspapers started worldwide release till now chapter 1059 (spoilers).
Chapter 956-957 thing made it even more concrete that Oda/Marines reveals all new bounties after the end of events in Wano.
Also WG and Oda is definitely putting emphasis on these schibukais former relationships with WG in there bounties boost.... like Bogard had said this speculation might be true.. What do you think ?
Some more things on the timeline
-The abolition of the Warlords happend in the end of the Reverie(c.956), the same day that BM invaded Udon (c.946/47) and that Teach set sail to Amazon Lily.
-Drake call with Koby happend six days after it(c.956) as BM and Kaido formed their alliance 3 days after the Reverie have already ended (c.954)
*The problem in this point is that when the scene change to Koby in the ship, the Viz translations say "in a steach of Sea" but the original say "at the current time in a streach of Sea", to diferenciate from the scenes of the Shichibukai news that happend days before.
-Teach attack on Amazon Lily, Croco attack on Karai Island and his call to Mihawk happend on the same day of the Koby-Drake call.
-The reunion of the Navy in chapter 957 happend after the call, as they already have gotten the news from Koby about BM-Kaido alliance, in the meeting seems like the Warlords haven't gotten their bounties upgrade yet, as the Navy had their hand full with escorting the Kings back home and also the 8 Revolutions. We even see Garp comming back from FI at the same time what indicated that after leaving the Reverie he spend a whole week traveling with the Ryugu family before he give them the news about Alabasta.
-The day after all this events is the day of the Raid
-A week after the Raid, the News with Luffy and Buggy as emperors is published, BM and Kaido defeat are made public and Ryokugyu arrive at Wano
-Even more days after it Buggy publish the Cross Guild posters, Marines make a reunion about it and the Supernovas leave Wano.
For the date of the bounties being issued seems like the Warlords new bounties were issued only after they have escaped capture from the Navy, in the same day Teach new one was issued and also the same day of the Raid.
So in this chapter Teach and Hancock bounties werent still their upgraded ones.