diff --git a/src/Qbil/Models/Invoice.php b/src/Qbil/Models/Invoice.php
index 4cf4706..63de370 100644
--- a/src/Qbil/Models/Invoice.php
+++ b/src/Qbil/Models/Invoice.php
@@ -27,6 +27,7 @@ public function __construct(Document $document, bool $includeInvoiceLines = true
         $this->orderNumber = Util::extract($document->HeaderFields, 'invoiceordernumber');
         $this->contract = Util::extract($document->HeaderFields, 'Inkoopcontract');
         $this->vat = Util::extract($document->HeaderFields, 'vatCode');
+        $this->dieselSurcharge = Util::extract($document->HeaderFields, 'DieselSurcharge');
 
         if ($includeInvoiceLines) {
             foreach (array_column(Util::extract($document->Tables, 'LineItem', 'TableRows'), 'ItemFields') as $line) {
@@ -36,7 +37,11 @@ public function __construct(Document $document, bool $includeInvoiceLines = true
                     Util::extract($line, 'LIT_VatExcludedAmount') ?? 0,
                     Util::extract($line, 'LIT_UnitPriceAmount') ?? 0,
                     Util::extract($line, 'LIT_Inkoopcontract') ?? null,
-                    $document->DocumentSubType
+                    $document->DocumentSubType,
+                    null,
+                    Util::extract($line, 'LIT_qtyPerBox') ?? 0,
+                    Util::extract($line, 'LIT_nrBoxes') ?? 0,
+                    $this
                 );
 
                 $this->addInvoiceLine($invoiceLine);
@@ -57,6 +62,7 @@ public function __construct(Document $document, bool $includeInvoiceLines = true
     private $orderNumber;
     private $contract;
     private $vat;
+    private $dieselSurcharge;
     private $invoiceLines = [];
 
     public function addInvoiceLine(InvoiceLineInterface $invoiceLine)
@@ -88,14 +94,6 @@ public function getSupplierInvoiceNumber()
         return $this->supplierInvoiceNumber;
     }
 
-    /**
-     * @return mixed
-     */
-    public function getAmount()
-    {
-        return $this->amount;
-    }
-
     /**
      * @return mixed
      */
@@ -175,4 +173,21 @@ public function getVat()
     {
         return $this->vat;
     }
+
+    /**
+     * @return mixed
+     */
+    public function getDieselSurcharge()
+    {
+        return $this->dieselSurcharge;
+    }
+
+    public function getAmount()
+    {
+        if (!$this->dieselSurcharge || $this->getDieselSurcharge() < 0) {
+            return $this->amount;
+        }
+
+        return (($this->dieselSurcharge * $this->amount) / 100) + $this->amount;
+    }
 }
diff --git a/src/Qbil/Models/InvoiceLine.php b/src/Qbil/Models/InvoiceLine.php
index f3fd27d..9861aee 100644
--- a/src/Qbil/Models/InvoiceLine.php
+++ b/src/Qbil/Models/InvoiceLine.php
@@ -10,7 +10,18 @@
 
 class InvoiceLine implements InvoiceLineInterface
 {
-    public function __construct(string $order, float $quantity, float $amount, float $price, string $purchaseContract, string $type, ?string $allocatedInvoice = null)
+    public function __construct(
+        string $order,
+        float $quantity,
+        float $amount,
+        float $price,
+        string $purchaseContract,
+        string $type,
+        ?string $allocatedInvoice = null,
+        ?float $qtyPerBox = 0,
+        ?int $noOfBoxes = 0,
+        ?Invoice $invoice = null
+    )
     {
         $this->order = $order;
         $this->quantity = $quantity;
@@ -19,6 +30,9 @@ public function __construct(string $order, float $quantity, float $amount, float
         $this->purchaseContract = $purchaseContract;
         $this->type = $type;
         $this->allocatedInvoice = $allocatedInvoice;
+        $this->qtyPerBox = $qtyPerBox;
+        $this->noOfBoxes = $noOfBoxes;
+        $this->invoice = $invoice;
     }
 
     private $order;
@@ -28,6 +42,9 @@ public function __construct(string $order, float $quantity, float $amount, float
     private $purchaseContract;
     private $type;
     private $allocatedInvoice;
+    public $qtyPerBox;
+    public $noOfBoxes;
+    public $invoice;
 
     /**
      * @return mixed
@@ -42,6 +59,10 @@ public function getOrder()
      */
     public function getQuantity()
     {
+        if ($this->qtyPerBox > 0 || $this->noOfBoxes > 0) {
+            return $this->qtyPerBox * $this->qtyPerBox;
+        }
+
         return $this->quantity;
     }
 
@@ -50,6 +71,14 @@ public function getQuantity()
      */
     public function getAmount()
     {
+        if (!$this->invoice) {
+            return $this->amount;
+        }
+
+        if ($this->invoice->getDieselSurcharge() < 0) {
+            return (($this->invoice->getDieselSurcharge() * $this->amount) / 100) + $this->amount;
+        }
+
         return $this->amount;
     }
 
@@ -60,7 +89,11 @@ public function getAmount()
      */
     public function getEstimatedAmount()
     {
-        return $this->amount;
+        if (!$this->invoice || $this->invoice->getDieselSurcharge() < 0) {
+            return $this->amount;
+        }
+
+        return (($this->invoice->getDieselSurcharge() * $this->amount) / 100) + $this->amount;
     }
 
     /**