weight.inc - total weight of goods

The function to get the total weight of goods and calculate the shipping charge (i.e. Charge Per Additional Pound (Over 1lb) doesn't appear to work. I get only the flat rate for one item added at checkout.

Also:

I noticed the weight attribute disappeared from the product form when both ups.inc and canada.inc were removed.
The Shipcalc _product_form hook was not doing its job:

 function weight_product_form(&$form) {
  $form['shipping_data']['product_weight'] = array(
    '#type' => 'textfield',
    '#title' => t('Product weight'),
    '#description' => t('The weight of the product (in %unit)', array('%unit'=> (variable_get('shipcalc_units', 'LBS')) ? t('pounds') : t('kilograms'))),
    '#default_value' => $form['#node']->product_weight
  );
}

Instead, if modified to be the same as the ups and canada files, it does indeed enhance the product form, and weight.inc does its job of adding a shipping charge to the cart:

function weight_product_attributes($form) {  
  $fields = array();
  $fields['weight'] = array(
    '#type' => 'textfield',
    '#title' => t('Product weight'),
    '#description' => t('The weight of the product (in %unit)', array('%unit'=> (variable_get('shipcalc_units', 'LBS')) ? t('pounds') : t('kilograms'))),
    '#default_value' => $form['#node']->product_attributes['weight']
  );
  return $fields;
}   

The original code seems to be copied from 'usps.inc', which may not work either.

Also, I would like to know where the shipcalc units are set, so I can work in Kilos or grams, if any one could help please.