Board Thread:Questions and Answers/@comment-24098163-20161017005318/@comment-29682895-20161017020945

The powers from your whole crew counts, including Friend Captain. As example: Your captain has 3 Slot Rate Boost; your 3rd crewmember has 1 Slot Rate Boost and your friend captain has 1 Slot Rate Boost. That's 5 in total so the level 1 will activate.

Took me a little while before I understood it as well.

Also a nice hint: you can power up the characters from the same "name". E.g: Luffy Gear 2nd and Luffy Gear 3rd are both from a seperate Luffy character evolution chain, but they're both "Luffy" so powering one up with the other once will give you a power.