I've done all my oil changes using the breather tube. Since it is vertical, I would think that any excess oil would drain down into the tranny case and not contribute to the problem. The amount of oil in the photos appears to be way more than what would adhere to the walls of the breather tube.
As to level, I drain out all the oil after it's warm; then I put in exactly one liter of 10-30W oil. I've never had a problem, though where I live it never gets below 40F and is usually 50F- 60F at this time of year. I can see if I were to use 80W gear oil, it could make the problem worse.
Also, I drive fairly slowly for about 2 miles to warm up the tires, so I'm never revving the motor when the oil is cold. (Old habits die hard!)
Since I have an early production run, I will get the warranty fix just to be on the safe side.