Silo structure and link juice flow - articles get highr ranking than the category(silo landing) page

Hi there,
I have been working with silo structure now.
In case you don't know about silo structure you can learn about it here. http://www.warriorforum.com/adsense-...wordpress.html

Anyway, I have noticed something - when I make a silo with a keyword and make related articles with long tail keywords, these articles tend to rank higher on Searps.

Let's say I have a silo about "dog training" and I have many sub pages(articles) with long tail keywords such as "dog training tricks" "dog training toilet" "dog training for puppies" etc. etc. The silo landing page looks like a typical landing page (not an article).

Now when you search for "dog training," one of my article pages such as "dog training tricks" (with the above example) comes up high on SERPs and the silo landing page actually does not show up on SERPs at all. I have several cases like this.

I have researched about this phenomenon and someone actually wrote about this on a report saying it can happen often because link juice tends to flow to sub pages. It says if you have sub-pages optimized with the same keyword as the main page, often the sub pages rank higher than the main page. (It didn't necessarily talk about silo structure though).

In my example case even though the articles are not intended to be optimized for "dog training" but since it is optimized for "dog training tricks," Google treated it as optimized for "dog training" and somehow decided the page is more important than the main page (silo landing page).

Getting ranked with article pages is better than not ranked at all, but conversion wise it is better if the landing page gets higher on SERPs and I want to do something about it.

Anyone who uses silo structure experiences this kind of phenomenon?
Do you think what the report says is true?
And also is there anything I can do to avoid this phenomenon?

FYI the landing page gets more backlinks than article pages if you were wondering, and the index page of the website gets most backlinks.

Thanks

PS the report is not in English, so I did not put a link to it.