Magento – Unable to get inventory status of configurable products

I am having some trouble and perhaps a few people here can expand my knowledge. Here is the code I am using to retrieve some information about a product on my cart page.

    if($product->getTypeId() == "configurable"){
        $sku = $_item->getSku();
        var_dump($sku);
        $product = Mage::getModel('catalog/product')->loadByAttribute('sku',$sku);
        $invStatus = $product->getResource()->getAttribute('product_inventory_status')->getFrontend()->getValue($product);
        var_dump($invStatus);
        $quantity = Mage::getModel('cataloginventory/stock_item')->loadByProduct($product)->getQty();
        var_dump($quantity);

If the product is found to be configurable I retrieve the sku of the simple product it is associated with and then set the product to that configured simple product. I then get the inentory status and the quantity of that product. And this is where the issue arises. This is the result of that vardump:

string(6) "421199" string(2) "No" string(6) "1.0000" 

When a similar methodology is enacted upon simple products I receive the following from the following code:

        var_dump($product->getSku());
        $invStatus = $product->getResource()->getAttribute('product_inventory_status')->getFrontend()->getValue($product);
        var_dump($invStatus);
        $quantity = Mage::getModel('cataloginventory/stock_item')->loadByProduct($product)->getQty();
        var_dump($quantity);

.

string(4) "DWCP" string(1) "Z" string(6) "0.0000"

The inventory status is definitely also set from the admin panel. Any suggestions or incites would be appreciated.

—

Also, if I add the simple product as the item itself (from another part of the site) then the string resolves to the correct value. It's when I'm fetching the product in this manner that non-resolvency becomes apparent.

Why doesn't magento handle products uniformly?? It makes NO sense at all.