Me too. I have also had a hard time figuring out how the system arrived at the numbers using the little info the website gives.
One tip: the make a green choice points often post separately, days later.
In your case, I assume the 2136 is for a bill that was $213.60 before tax, the elite is the bonus for being a platinum, the 500 is the welcome amenity and the 2000 is the current megabonus.
A second tip: I always ask the front desk how much the points are before choosing my welcome amenity. I cannot remember the amenity for 30 brands off the top of my head.