Oda decided to age Momo 20 years as expected. he could not let the chance go, since Momo was supposed to be 28 years old if he didn't time travel.
he already made the relation between King and Queen similar to that of Zoro and Sanji, gave Marco who was able to handle both of them and even some of their minions for a long time alone a bounty of 1.374B. it. to be honest I cannot see Oda let the chance go either and gave King and Queen a bounty similar to that between Sanji and Zoro either die difference will be 10 millions or 100 millions , so King would be either 1.33 B or 1.42B but i tend to the first because i cannot see King have a higher bounty than Marco.