Points in the Pass tab appear only after you eliminate an enemy in the Challenge. While you are attacking an enemy, points are added to the Challenge tab.

Let's say you eliminate an enemy in the Challenge and earn 100 points during the attack. These 100 points will then appear in the Pass tab. A new enemy appears, and in the course of the next attack, you earn another 10 points. The Challenge tab will now display 110 points, but the Pass tab will still show 100 — because the new opponent hasn't been eliminated yet, and therefore the Challenge is not yet complete.