20,000 Pokos is the goal amount of Pokos in Pikmin 3 (Flish addition). The President says he is thankful that you collected all 20,000 pokos he spent on a meal because he didn't want to eat his all grass diet agian. after all 20,000 pokos are collected, Olimar, Louie, and Saggitarius head home only to find the president want to find more treasures so he joins Olimar, Louie, and Saggitarius and you head down to the pikmin planet. it isn't ever said exactly why this happens, but you can do whatever you want now.