Nissan and Infiniti has "H" and "L" markings on their dipsticks. A few folks at an Infiniti-focused forum insist that the proper level is at "H" and you must keep it there, all the time. If it goes below "H", you have to add oil. My belief is anywhere in between the two marks is perfectly acceptable.
What do "H" and "L" mean ? No one seems to know but logic says "high" and "low", right ? If so, I'd think right in the middle would be the ideal level. Filled to "H" could mean it's filled on the high side and filled to "L" means it's on the low side. Does that mean you have to drain some oil or add some oil if it's at either mark ? No idea.... The manual does say oil level should be "within the range" (meaning the two marks). If it's below, add oil, but it doesn't say to drain oil if it's over.