iTunes Store Popularity Bar in search results vs when clicking album title

I just have a general question about understanding the popularity bar in the iTunes music store.

When I do a search for a music album, the popularity bar has the songs on the album listed in order by a certain popularity, but when I click on the actual album title, it then shows me the order of the songs as they are listed on the album with another popularity bar.

My question is, can you tell me the difference between the two popularity bars for the songs on an album when typing in an artist name in the search box versus when clicking on the actual album title and seeing the popularity bar again?

Both may not match for the same song as far as the popularity on the album.

Thanks