As the series progressed, it's pretty obvious that there was, and still is, a bit of bounty inflation going on.
Luffy, as well as Ace and Robin for that matter, should have had significantly higher bounties given the danger they supposedly represent on a narrative level.
Jinbe, a former Shichibukai, only gets a 100 milli and some change boost despite leaving the Shichibukai, betraying the government, participating in the war and immediately joining a Yonkou after.
Law, for his troubles, only gets a 60 milli boost despite similarly betraying the government and assisting in the Doffy take down.
Going by the logic here, Boa, Mihawk, and Weevil should only get between 60 milli and 200 milli boost at the most with their new bounties. But we know that won't be the case, since these characters are going to get bounties that keep them relevant at this point in the series.