Can you explain if this method of khums is correct-
Year 1 I have net profit 1,000usd. Khums is 200. Remaining is 800usd.

Year 2- The remaining khums paid 800usd I used it. And made NEW income of 1,000usd.
(Should i deduct 800? then pay khums on 200?)

Yes. You have to pay the khoms of 200 only.