If you are restructuring the leaderboard and want to keep the previous times, you could section it off by version number.

With the addition of Skull Island, it falls under "Update 27", so for full game leaderboard old times, you can do the category Update 26 and have the "classic heists" be subcategories.

For the new Update 27, there'll already have the subcategories 10k, 30k, 50k, since you edited it that way.