I've filled to the Max line for most of my life too.
When I did my first M271 oil change I knew something was not right. The stated fill volume is 5.5L but something like 6.5 L came out and the oil hadn't even been up to Max. So I put a carefully measured 5.5 L back in and it came only 1/4 of the way between Min and Max. I don't know if it's the dipstick that's wrong or the stated 5.5 L fill volume but If I had to guess I was going to trust the 5.5L as being accurate. Not wanting to risk overfilling the engine, I've continued to add 5.5L for the last 8 oil changes. The car has no electronic dipstick (thankfully) but it does have a low level warning which has never actuated. I'm happy there is adequate oil in there for the safe lubrication of the engine especially as it doesn't use any measurable amount between changes.
I don't run my BMW motorcycle anywhere near Max either. BMW specifically advise not to but that's another story.
