I also forgot to mention that you will need to edit line 186-194

Code:
<td class="dataTableContent" align="right" valign="top"><b>' .
$currencies->format($order->products[$i]['final_price'], true, $order->info['currency'], $order->info['currency_value']) .
($order->products[$i]['onetime_charges'] != 0 ? '<br />' . $currencies->format($order->products[$i]['onetime_charges'], true, $order->info['currency'], $order->info['currency_value']) : '') .
'</b></td>' . "\n" .
' <td class="dataTableContent" align="right" valign="top"><b>' .
$currencies->format(zen_add_tax($order->products[$i]['final_price'], $order->products[$i]['tax']), true, $order->info['currency'], $order->info['currency_value']) .
($order->products[$i]['onetime_charges'] != 0 ? '<br />' . $currencies->format(zen_add_tax($order->products[$i]['onetime_charges'], $order->products[$i]['tax']), true, $order->info['currency'], $order->info['currency_value']) : '') .
'</b></td>' . "\n" .

upon the successful deletion you will see that only one populates