I'm not sure why, but the epic boosters are worth less than the exact same common booster variant.
Just as an example: Ginseng Root is worth 3520 for the common booster, 32400 for the rare booster, but only 1368 for the epic booster. The price decreases by 31k despite being twice as powerful and lasting twice as long. It would make more sense if the epic booster was worth 64800 (or more because it takes up one less item slot, making it more valuable to the player). The same goes for the jujubes and cordyceps. I don't have an epic chlorella, but I can only guess that it has the same issue.