I really have no idea of this 11 13 1AZ, but what I do all the times is to hand tighten first then use the wrench to tighten the drain nut a bit more. That's it. Do not over tighten the drain nut .....

 

I beleive the 11 13 1AZ is a reference to the tightening torque table on the last page of the technical bulletin. Take a look.

Also, when I first changed the oil on my 550 (at 1,500 miles), I noticed the following. The oil pan is apparently painted at the factory with the drain plug and copper washer installed. Therefore, when I took the drain plug out of the oil pan for the first time, the copper washer appeared to be part of the drain plug becuase they were "painted together". I had to snap the copper washer off the plug.

In other words, there is most certainly a copper washer on the drain plug when the car comes from the factory. It's just difficult to discern it from the plug itself becuase it has been painted black like the plug and they are stuck together. If you don't remove the original one that has been "painted on" the plug, you will have two of them. Probably not a good idea.