Saturation effect can't have duration applied to a potion, but can using /effect

So i was trying to make a potion that had saturation 4 for 6000 ticks.  So that i could make items they could buy to keep their hunger full for a set amount of time. But when i tried.

What i did:

/give @p minecraft:potion{CustomPotionEffects:[{Id:23b,Amplifier:4b,Duration:6000}]} 1

What should of happened:

Have gotten a potion when drank, refills your hunger completely for 5 minutes.

What actually happened:

Just filled my hunger for a second.

How to make it work:

/effect give {name} minecraft:saturation 600 4

I dont see why the saturation effect shouldnt be allowed to have a duration tag attached to it when its in potion form but can in a base command. Please add it.