Changes to keyword hierarchy

[mephisto2061]

So let's say you add a keyword "parent" to 5 images. 

next you add a keyword "child" to 3 new images (note "child" is currently not under "parent" in the keywords panel).

next you drag "child" in the keywords panel to inside "parent".

the numbers next to "parent" and "child" in the keywords panel now say 5 and 3 respectively.

Q - should it not automatically update "parent" to 8?  In fact, when I click the little arrow on the right of "parent", it searches and displays all 8 images (as it should)

furthermore, if I click the little arrow on the right of "child", it picks up 3 images (as it should), if I now select the 3 images there is a checkmark to the left of child (as there should be) but there is a hyphen to the left of parent.

Q - should it not show a proper checkmark next to parent too, now that the parent keyword has been applied to the 3 child images?

In fact, if I click on the hyphen while maintaining the selection of the 3 child images, the number next to it updates to 8 and the hyphen changes to a checkmark.

Why does it behave like this?

[mephisto2061]

To ask this question in a different way, what is the conceptual difference between explicitly adding a top level keyword vs having the top level keyword being added automatically by adding one of its lower level "child" keywords. 

I don't see why there should be any conceptual difference but for some reason, Lightroom treats them differently - the former places a checkmark next to the top level keyword and includes it in the keyword counter, whereas the latter places a hyphen and does not include it in the counter.

Thoughts?