How does DOTA2 witch doctor's curse calculate the damage?

The whole curse time is 12 seconds, during which you will lose 5/ 10/ 15/20 points of blood per second according to your skill level, and generate bonus damage every 4 seconds, which occurs three times in total. Every loss of 100 points of life will generate16/24/30. If you don't count the skill damage per second, if the hero takes 500 damage in the first 4 seconds, there will be 200 damage in the first jump, 280 damage in the second jump and 360 damage in the third jump.