diff --git a/modules/invoice/classes/Invoice.php b/modules/invoice/classes/Invoice.php
index 0eb27783..f8d0bfb8 100644
--- a/modules/invoice/classes/Invoice.php
+++ b/modules/invoice/classes/Invoice.php
@@ -70,7 +70,7 @@ class Invoice {
 		// Service Billing
 		$iio->item_type = 0;
 
-		$this->_io->subitem_add($iio,$this->_io->account->country);
+		$this->_io->add_sub_item($iio);
 
 		// Check if there are any charges
 		$c = ORM::factory('Charge')
@@ -89,7 +89,7 @@ class Invoice {
 			$iio->date_stop = $co->date_orig;
 			$iio->item_type = $co->type;
 
-			$this->_io->subitem_add($iio,$this->_io->account->country);
+			$this->_io->add_sub_item($iio);
 		}
 
 		return $this;
diff --git a/modules/invoice/classes/Model/Invoice.php b/modules/invoice/classes/Model/Invoice.php
index 18b5e712..52a8c5eb 100644
--- a/modules/invoice/classes/Model/Invoice.php
+++ b/modules/invoice/classes/Model/Invoice.php
@@ -43,7 +43,7 @@ class Model_Invoice extends ORM_OSB implements Cartable {
 
 	// Items belonging to an invoice
 	protected $_sub_items_load = array(
-		'invoice_item'=>'service_id,item_type,date_start,date_stop',
+		'invoice_item'=>array('service_id','item_type','date_start','date_stop'),
 	);
 
 	protected $_compress_column = array(
@@ -58,6 +58,12 @@ class Model_Invoice extends ORM_OSB implements Cartable {
 		return new Cart_Item(1,sprintf('Invoice: %s',$this->refnum()),$this->due());
 	}
 
+	public function add_sub_item(Model_Invoice_Item $iio,$taxed=FALSE) {
+		$iio->add_sub_item($this->account->country,$taxed);
+
+		$this->subitem_add($iio);
+	}
+
 	/**
 	 * Return if this invoice is already in the cart
 	 */
@@ -403,17 +409,6 @@ class Model_Invoice extends ORM_OSB implements Cartable {
 		return $this->saved();
 	}
 
-	/**
-	 * Add an item to an invoice
-	 */
-	public function subitem_add(Model_Invoice_Item $iio,Model_Country $co,$taxed=FALSE) {
-		$iio->subitem_add($co,$taxed);
-
-		array_push($this->_sub_items,$iio);
-
-		$this->_sub_items_sorted = FALSE;
-	}
-
 	/**
 	 * Return a list of invoice items for this invoice.
 	 * @param type [CHARGE|CREDIT|ALL]
diff --git a/modules/invoice/classes/Model/Invoice/Item.php b/modules/invoice/classes/Model/Invoice/Item.php
index ca06ae6d..9df2a2a2 100644
--- a/modules/invoice/classes/Model/Invoice/Item.php
+++ b/modules/invoice/classes/Model/Invoice/Item.php
@@ -33,9 +33,38 @@ class Model_Invoice_Item extends ORM_OSB {
 
 	// Items belonging to an invoice item
 	protected $_sub_items_load = array(
-		'tax'=>FALSE,
+		'tax'=>array(),
 	);
 
+	/**
+	 * Add tax to our item
+	 *
+	 * @param Model_Country the country to get the tax rates
+	 * @param Boolean Is this price inc/ex tax
+	 */
+	public function add_sub_item(Model_Country $co,$taxed=FALSE) {
+		$orig = $this->subtotal();
+		$tax = 0;
+
+		foreach ($co->tax->find_all() as $to) {
+			$iito = ORM::factory('Invoice_Item_Tax');
+
+			$iito->tax_id = $to->id;
+			$iito->amount = Currency::round($taxed ? ($orig-$orig/(1+$to->rate)) : $orig*$to->rate);
+
+			$tax += $iito->amount;
+			$this->subitem_add($iito);
+		}
+
+		// If taxed, we need to reduce our base_rate to a pre-tax amount
+		if ($taxed) {
+			$this->price_base -= Currency::round($tax/$this->quantity,1);
+
+			// If there is any rounding, we'll take it off the last IITO
+			$iito->amount += $orig-$this->total();
+		}
+	}
+
 	// The total of all discounts
 	public function discount() {
 		return Currency::round($this->discount_amt);
@@ -138,37 +167,6 @@ class Model_Invoice_Item extends ORM_OSB {
 		return $this;
 	}
 
-	/**
-	 * Add tax to our item
-	 *
-	 * @param Model_Country the country to get the tax rates
-	 * @param Boolean Is this price inc/ex tax
-	 */
-	public function subitem_add(Model_Country $co,$taxed=FALSE) {
-		$orig = $this->subtotal();
-		$tax = 0;
-
-		foreach ($co->tax->find_all() as $to) {
-			$iito = ORM::factory('Invoice_Item_Tax');
-
-			$iito->tax_id = $to->id;
-			$iito->amount = Currency::round($taxed ? ($orig-$orig/(1+$to->rate)) : $orig*$to->rate);
-
-			$tax += $iito->amount;
-			array_push($this->_sub_items,$iito);
-		}
-
-		// If taxed, we need to reduce our base_rate to a pre-tax amount
-		if ($taxed) {
-			$this->price_base -= Currency::round($tax/$this->quantity,1);
-
-			// If there is any rounding, we'll take it off the last IITO
-			$iito->amount += $orig-$this->total();
-		}
-
-		$this->_sub_items_sorted = FALSE;
-	}
-
 	// This total of this item before discounts and taxes
 	public function subtotal($format=FALSE) {
 		$result = $this->price_base*$this->quantity;