Coupon calculates but after 9% or more, doesn't sent correct amount to payment gateway (Cybersource)

It does work with the gateway because again, the first coupon works as it should.

Let me clear this up in case there is a misunderstanding. I create an additional coupon for another campaign and the calculations work on the checkout page but the wrong (undiscounted) amount is getting sent to cyber source.

I'm NOT trying to get 2 coupons to work together. These are 2 separate coupons for 2 different discounts. Just the only coupon that actually works is the first coupon i've ever created. The second coupon has all the same settings and does the calculations but doesn't send the correct amount to the payment gateway.

Let me know of what I can do to trouble shoot this problem to help you with the fix.

After running multiple tests, We figured out that there is a specific amount that causes the payment gateway to receive the undiscounted price w/ the correct tax. If the discount is more than 8%, It breaks. I will run more tests today to see if the amount of the coupon that breaks it instead of the number of coupons created.

Relevant Modules & Versions:
Cart 7.x-3.2
Discount Coupons 7.x-2.1-alpha7
Token 7.x-1.4
Entity API 7.x-1.0-rc3
Views 7.x-3.5

Modules Enabled:
- ALL of UC core.
- Catalog, Payment, Product Attributes, Reports, Shipping, Shipping quotes, Tax Reports, Taxes
- Product Kit, Stock
- Flat Rate
- Credit Card, Cyber Source, Discount Coupons

Payment Gateway: Cyber Source
Payment Method: SOAP Toolkit API - Everything here is configured correctly here.

Shipping: Flat Rate (We add $30 for next day air)

Coupon Settings:
- Coupon is Active is checked.
- Discount amount [we are using percentage based discounts. If the discount is BELOW 9%. It works as it should. If its 9% or HIGHER, it sends the undiscounted amount to the payment gateway.] The calculations on the checkout page are ALWAYS correct. No matter the amount of the coupon percentile.
- Apply Discount to: We have tried with Order Subtotal, and Total of matching products. Both cause the same results.
- Redemption Amounts Restrictions are both blank.

This link mentions a similar issue except it is with paypal.

We have also tried with a FRESH & completely bare Drupal 7, UC 7.x-3.2, & Discounted Coupons 7.x-2.1-alpha7. It still did not work.

The problem lies between these lines;

    // Add the order total information.
    $purchaseTotals = new stdClass();
    $purchaseTotals->currency = $currency;

    // Specify the total to charge if it's less than the order total.
    if ($amount < $order->order_total) {
      $purchaseTotals->grandTotalAmount = $amount;
    }
    $request->purchaseTotals = $purchaseTotals;

    // Separately add products and line item into the request items object if
    // we're charging the full order total.
    if (round($amount, 2) == round($order->order_total, 2)) {
      $request->item = array();
      $counter = 0;

      // Add the products to the item array.
      foreach ($order->products as $product) {
        $obj = $request->item[] = new stdClass();

        $obj->productName = $product->title;
        $obj->unitPrice = $product->price;
        $obj->quantity = $product->qty;
        $obj->productSKU = $product->model;
        $obj->productCode = 'default';
        $obj->id = $counter;

        $counter++;
      }

      // Add the line items to the item array.
      $discount_amount = 0;
      foreach ((array) $order->line_items as $line_item) {
        // Handle negative line items.
        if ($line_item['amount'] < 0) {
          $discount_amount += -$line_item['amount'];
        }
        // Skip subtotal line items.
        elseif (strpos($line_item['type'], 'subtotal') === FALSE) {
          $obj = $request->item[] = new stdClass();

          $obj->productName = $line_item['title'];
          $obj->unitPrice = $line_item['amount'];
          $obj->quantity = 1;
          $obj->productSKU = $line_item['type'] . '_' . $line_item['line_item_id'];
          $obj->id = $counter;

          $counter++;
        }
      }
    }

    // Add the total order discount into the request.
    if ($discount_amount != 0) {
      $request->purchaseTotals->discountAmount = $discount_amount;
    }

Here is a successful order w/ a discount of 8%:

    [purchaseTotals] => stdClass Object
        (
            [currency] => usd
            [grandTotalAmount] => 321.58
            [discountAmount] => 23.92
        )

    [item] => Array
        (
            [0] => stdClass Object
                (
                    [productName] => Signature Pendant - 14K Yellow Gold
                    [unitPrice] => 299.00000
                    [quantity] => 1
                    [productSKU] => USI2541YR5J
                    [productCode] => default
                    [id] => 0
                )

            [1] => stdClass Object
                (
                    [productName] => Next Day Air
                    [unitPrice] => 30.00000
                    [quantity] => 1
                    [productSKU] => shipping_158
                    [id] => 1
                )

            [2] => stdClass Object
                (
                    [productName] => FL TAX
                    [unitPrice] => 16.50480
                    [quantity] => 1
                    [productSKU] => tax_160
                    [id] => 2
                )

        )

Here is what a failure looks like with a 10% discount. The threshold to break it is 9% thou;

    [purchaseTotals] => stdClass Object
        (
            [currency] => usd
            [discountAmount] => 29.9
        )

    [item] => Array
        (
            [0] => stdClass Object
                (
                    [productName] => Signature Pendant - 14K Yellow Gold
                    [unitPrice] => 299.00000
                    [quantity] => 1
                    [productSKU] => USI2541YR5J
                    [productCode] => default
                    [id] => 0
                )

            [1] => stdClass Object
                (
                    [productName] => Next Day Air
                    [unitPrice] => 30.00000
                    [quantity] => 1
                    [productSKU] => shipping_155
                    [id] => 1
                )

            [2] => stdClass Object
                (
                    [productName] => FL TAX
                    [unitPrice] => 16.14600
                    [quantity] => 1
                    [productSKU] => tax_157
                    [id] => 2
                )

        )

The difference is that "grandTotalAmount" is getting populated on 8% or less of a discount. Anything after that and "grandTotalAmount" doesn't get generated. Not sure but is this correct?

    // Add the total order discount into the request.
    if ($discount_amount != 0) {
      $request->purchaseTotals->discountAmount = $discount_amount;
    }

Almost seems like something is missing inside the if statement.

Fixed it by changing the code to the following;

// Specify the total to charge if it's less than the order total.
    if ($amount <= $order->order_total || $amount >= $order->order_total) {
      $purchaseTotals->grandTotalAmount = $amount;
    }
    $request->purchaseTotals = $purchaseTotals;

Yea I had a feeling my fix was dirty but this was on a production site that needed an immediate fix. It fixed the problem so I left that as is. I don't know how to submit a proper patch unfortunately but with the information longwave gave. I can make an attempt to create a clean fix.

Indeed it worked.