Max points for Useful Actions is . . . bugged

The landing is actually irrelevant… you get 80% for the UA and the missing 20% for landing… it’s just easier to add it so you can see you never get 100% of the reward on the stat card, only 92%.

You could also just calculate 80% of the expected reward. So 24,450 x 80% = 19,560

Instead he gets about 18,000 per UA.

Where is the missing 1,560?

So the reward for landing is displayed elsewhere in the screenshot? The figures he shows will only show 80% anyway, no matter if he landed or not?

(I am not familiar with Sim Battles)

No.

You can hover over a different place and see it in each battle report though.