Board Thread:New on Death March Wikia/@comment-66.42.136.26-20160512162004/@comment-109.133.122.71-20160718025959

It has also been hinted at that skill levels take less points as your charcter level rises, i believe it was when Arisa reset her skills and had a feeling a certain skill cost more points in the past when she was still low leveled.

So the reason Satou is has op skills is because by instantly levelling to 300+ the point cost immediately went down.

If someone else gradually levelled up to 300 and spent their points as they went they would have nowhere near as many skills.