As someone who does uber eats for some side cash (I have a very small and fuel effecient car, so it actually works out gas wise for me), the 11 dollars was the total service charge. Uber then breaks it down by what they take (the first party part, not included), and any other fees are in a seperate Third party section. So from my perspective of 11 dollars total, with 6 for the third party (which they absolutely pass onto the driver), the missing 5 could be made up by the Uber first party charges.
Now I can't confirm this, I'm not on his account, and he hasn't posted it yet. But I would put a nickel on the other 5 bucks being paid directly to Uber. Which again, not uncommon.
Here's an example from a delivery I did the other day, I can get more screenshots if you want. But out of the 22 dollars the customer paid for the delivery, I received 5.61 before tip. The rest went to uber [1]