[tock172]

Yeah that is definitely the full mark, but don't feel too bad about it. The gap on the right side is definitely misleading.

As far as overfilling is concerned, I know individuals running 7, 7.5 and even up to 8 quarts in various twin-cam BMW straight sixes from the M50 to the current crop of turbo engines. Oil consistently drains from the heads of BMW engines during high speed corning which leads to lifter tick. Many of these engines are high mileage and burn a bit of oil as well.

It's very possible you're burning a bit of oil at 156k miles. I wouldn't worry about the amount that drained out if you're getting an accurate full reading. However, if you want to start measuring from a clean slate, your next oil service is the opportunity to do it, as you know exactly how much your poured in this time.