It’s makes sense. King and Marco are in the same league regarding their strength but King is more violent. So King having a higher bounty is fine.
Oda's been paralleling them this entire arc.
King knocks the Chanter down the waterfall 1st, then Marco does it later.
Marco was offered a spot in Shanks crew, later King is done the same in Linlin's
Both flying Zoans with fire-y themes.
Both the strongest subordinates to the "World's Strongest" titled captain
They're almost equals IMO