im not 100% sure if I understood the question but I'll try anyway.
From my understanding you get 50+ if you kill a enemy who is low on hp, you get 100+ if you kill a enemy from full hp to death and you get 150+ for a headshot.
I guess your talking about assists and it works pretty much the same, if you and your team mate shoot the same guy who got full hp you get 40+ and then you simply get lower depending on the HP of the enemy down to nothing.
I might be completly wrong and as I said im not completly sure if I understood your question so if this answers your question then yay, if not then booo!