Omnifocus 4: Natural Order and Preserve Hierarchy - How Do These Work?

I’m really liking how OF4 is coming along and the new features that allow you more freedom in how you move around tasks.

I’m just wondering about the features for Perspectives.

It gives an option under the Flexible section to chose the initial order as ‘natural order’. Can anyone explain what this means? I tried it and I couldn’t understand what logic it used to sort the tasks.

Also, would someone be able to explain what ‘preserve hierarchy’ does? If I start moving around tasks in a flexible list like this, does it mess with the hierarchy in any way? Or does this only factor in if the perspective allows for projects and action groups?