how to extend a custom module

Question

I am writing 2 modules, one dependent on the other and both extend the user profile page. The first one is order_history and the other one order_details. The concept is order_history pulls out a list of all orders and order_details displays only 1 order but with details.

Now the problems are:

1. I am able to access http://localhost/drupal/user/1/order_history and I get the table. But when I click on the link, I am taken to http://localhost/drupal/user/1/1001.
2. When I directly put the url http://localhost/drupal/user/1/order_history/1001, I see the order_history table but not the message.

Can't figure out what's wrong with the code. Please point to the right direction.

So here is the code for both:

order_history.module

function order_history_menu(){
    $items = array();
    $items['user/%user/order_history'] = array(
        'title'             =>  'Order History', 
        'page callback'     =>  'drupal_get_form', 
        'page arguments'    =>  array('order_history_form'), 
        'access arguments'  =>  array('access order history'),
        'type'              =>  MENU_LOCAL_TASK,
        );
    return $items;
}

function order_history_form($form) {
    $output_form='<div class="form-wrapper">
<table style="width:100%;">
    <thead>
        <tr>
            <th>Order Number</th>
            <th>Order Date</th>
            <th>Order Status</th>
            <th>Amount</th>
        </tr>
    </thead>
    <tbody>
        <tr>
            <td>
                <a href="1001">1001</a>
            </td>
            <td>2014-04-01</td>
            <td>Shipped by seller</td>
            <td>$468.89</td>
        </tr>
    </tbody>
</table>
</div>';

    $form['order_history'] = array(
                    '#type' => 'markup',
                    '#title' => t('Order History'),
                    '#markup' => drupal_render($output_form),
            );
    return $form;
}

order_details.module :

function order_details_menu(){
    $items = array();
    $items['user/%user/order_history/%order_number'] = array(
        'title'             =>  'Order Details', 
        'page callback'     =>  'order_details', 
        'page arguments'    =>  array('%user','%order_number'), 
        'access arguments'  =>  array('access order details'),
        'type'              =>  MENU_LOCAL_TASK,
        );
    return $items;
}

function order_details($user, $order_number){
    drupal_set_message('Response from order details.');
}