Detail Item GetLocation - Error Z elevation

I have two families created from 1) Detail Item and 2) Detail Item line based that I want to get their locations. I use FamilyInstance.Location node and I also tried Element.GetLocation node. While getting X and Y works perfectly, I came across with a weird Z value.

For an element created from Detail Item line based, I got Z = 0.00, which I expected that. However for an element created from Detail Item, there is Z elevation value tied to an element, which is a surprise to me. Looking in further, I found that this Z value ties to view range cut plane offset value. I changed this cut plane offset a few times and Z value matched that.

Has anyone come across this? Is this normal?