HTML5 semantic structuring of article and section on web site with multiple sub levels

Question

Which of the following - if any - is the most correct way of using the article and section elements on a web site with multiple sub levels?

The first example creates this flat outline like this.

1. Company Name
   1. Segment Navigation
2. Segment Name
   1. Segment Sub Navigation
3. Product Name
   1. Product Sub Page Navigation
   2. Product sub page 1 title
4. Footer

...and looks like this

<header> <!-- MAIN NAVIGATION -->
    <h1><a>Company Name</a></h1>
    <nav>
        <h1>Segment Navigation</h1>
        <ul>
            <li><a>Segment 1</a></li>
            <li><a>Segment 2</a></li>
            <li><a>Segment 3</a></li>
        </ul>
    </nav>
</header>
<header> <!-- SUB NAVIGATION -->
    <h1><a>Segment Name</a></h1>    
    <nav>
        <h1>Segment Sub Navigation</h1>
        <ul>
            <li><a>Product 1</a></li>
            <li><a>Product 2</a></li>
            <li><a>Product 3</a></li>
        </ul>
    </nav>
</header>
<header> <!-- PRODUCT PAGE NAVIGATION -->
    <h1><a>Product Name</a></h1>    
    <nav>
        <h1>Product Sub Page Navigation</h1>
        <ul>
            <li><a>Product sub page 1</a></li>
            <li><a>Product sub page 2</a></li>
            <li><a>Product sub page 3</a></li>
        </ul>
    </nav>
</header>
<article>
    <h1>Product sub page 1 title</h1>
    <p>Content from Product sub page 1<p>
</article>
<footer>
    <h1>Footer</h1>
    <p>Footer content</p>
</footer>

The second example creates a tree structure outline like this

1. Company Name
   1. Segment Navigation
   2. Segment Name
      1. Segment Sub Navigation
      2. Product Name
         1. Product Sub Page Navigation
         2. Product sub page 1 title
2. Footer

...and looks like this

<header> <!-- MAIN NAVIGATION -->
    <h1><a>Company Name</a></h1>
    <nav>
        <h1>Segment Navigation</h1>
        <ul>
            <li><a>Segment 1</a></li>
            <li><a>Segment 2</a></li>
            <li><a>Segment 3</a></li>
        </ul>
    </nav>
</header>

<section> <!-- SEGMENT SECTION -->
    <header> <!-- SUB NAVIGATION -->
        <h1><a>Segment Name</a></h1>    
        <nav>
            <h1>Segment Sub Navigation</h1>
            <ul>
                <li><a>Product 1</a></li>
                <li><a>Product 2</a></li>
                <li><a>Product 3</a></li>
            </ul>
        </nav>
    </header>

    <section> <!-- PRODUCT SECTION -->
        <header> <!-- PRODUCT PAGE NAVIGATION -->
            <h1><a>Product Name</a></h1>    
            <nav>
                <h1>Product Sub Page Navigation</h1>
                <ul>
                    <li><a>Product sub page 1</a></li>
                    <li><a>Product sub page 2</a></li>
                    <li><a>Product sub page 3</a></li>
                </ul>
            </nav>
        </header>

        <article>
            <h1>Product sub page 1 title</h1>
            <p>Content from Product sub page 1<p>
        </article>
    </section>
</section>

<footer>
    <h1>Footer</h1>
    <p>Footer content</p>
</footer>

Answer 1

Both are fine, but mean different things. Go with whichever outline matches your intent for the structure.