Example, 1040NR line23 is $10,000.
And Line22 is $2000 through item L of Sch OI 1040NR page5.
The amount was displayed correctly on line22($2,000). 
But line 22 income exempt didn't apply to any line. I think line23 should be $8,000, not10,000.(10,000-2,000) Why is it not applicable?