subdude

Good Morning, I have a 2013 S4. During the most recent oil change during the inspection of the oil pan drain plug mating surface it was noted that there are 2 diametrically opposed notches stamped into the mating surface. They appear to be there by design as they are located exactly 180 degrees apart in the periphery of the mating surface and also consistent in depth(about 1-2 mm). I am at a loss in understanding what function they could possibly serve and am trying to determine if they are in fact there by design. The oil pan has an oil leak from the drain plug. We have tried both copper crush washers as well as the aluminum type, neither was effective at forming a proper seal.

My question to the group is if these notches are there by design, has anyone else noted them?

Thank You,