Better Performance Gives Better Rank Points?

So i was wondering,

• if you do well (like A or S after game) do you get more rank points?
• Or like if you didnt do well after winning, do you get less rank points?
• How about when you lose. Do you get penaltied less if you get a high A or S?
• Do you lose more points like if you have B or C?
• Or none of that matter, What matters is the average rank of your team vs the avg rank of the enemy team?