People who can read the panels actually understood that during King vs Zoro.
Oda made Luffy part of yonkou when he got 1,5b so he gave on purpose to marco 1,37b and king 1,39b as long they don't end up above luffy. But for King, he added the information that he would have got +100m if WG knew who he was.
So 1,49b is the real bounty of King so still below the 5th yonkou.
Poor King-chan always getting downplayed because of others