Contacted
You are 100% correct. What it states is that aircraft must arrive with enough fuel to allow for up to 20 minutes, not an 'extra' 20 minutes. This is simply to allow for the 'no delay' scenario where aircraft will be expected to assume 'up to 20 minutes' without being given an ETA. Same as UK.
As I keep saying until i'm blue in the face, EK's fuel policy and that of many other operators covers that. Some airlines don't have alternate fuel, and it's for those airlines that the requirement was published. Some operators were arriving with destination fuel, a small amount of contingency and final reserves!
Reading all this, I have to agree with acegreaser's post.
Harry