Discount invoiced different from Discount Amount so total due>0

[anusha_das]

When an order is placed along using store discount(10%) and coupon discount(10%), calculcations on backend are done as follows: 

Coupon discount applied to subtotal first, and then store discount applied to the (subtotal-coupon discount). However, on Magento, both the discounts are added up and applied together to the subtotal ie 20%. This way, discount invoiced is more than the actual discount amount and total paid is lesser than the grand total so even after order is completed, total due>0. Any help would be much appreciated.

Heres a screenshot of the order details, where discount amount (5.66+2.05=7.71) is different from actual discount (7.33).

[Rahul Gupta]

@anusha_das please share the link of the screenshot as it is visible once approved by any moderators.

Thanks

[Damian Culotta]

Hi @anusha_das,

Is the Store Discount another coupon?

Can you share how those two discount coupons were configured?

[anusha_das]

No store discount is not a coupon. Coupon discount was configured manually using Shopping Cart Rules in the admin panel. Store discount calculated using so:

function determineDiscountTotal($grandTotal, $discountData, $shippingMethod = 1){
    
    $discountData = cleanUpDiscountData($discountData);
    
    $discount = [];
    
    $grandTotal = (float)$grandTotal;
    
    foreach(array_keys($discountData) as $method){
        $discountAmount = 0;
        
        $methodData = $discountData[$method]["data"];
        
        $priceLevels = array_keys($methodData);
        $priceLevels = array_map(function($val){
            return (float)$val;
        }, $priceLevels);
        foreach($priceLevels as $priceLevel){
            if($grandTotal >= (float)$priceLevel && $discountAmount < (float)$methodData[(string)$priceLevel]){
                $discountAmount = (float)$methodData[(string)$priceLevel];
            }
        }
        $discount[$method] = $discountAmount;
    }
    
    $toReturn = null;
    switch ((int)$shippingMethod) {
        case 1:
            if (isset($discountData['dlvry'])) {
                $type = isset($discountData['dlvry']['type']) ? $discountData['dlvry']['type'] : null;
                if($type == 1){ // percentage
                    $toReturn = $grandTotal * $discount['dlvry'] / 100;
                } else {
                    $toReturn = $discount['dlvry'];
                }
            }
            break;
        case 2:
            if (isset($discount['pickup'])) {
                $type = isset($discountData['pickup']['type']) ? (int)$discountData['pickup']['type'] : null;
                if($type == 1){ // percentage
                    $toReturn = $grandTotal * $discount['pickup'] / 100;
                } else {
                    $toReturn = $discount['pickup'];
                }
            }
            break;
        default:
            break;
    }
    return $toReturn;
}

I know there is a problem in the logic of the code above because when store discount is configured as a coupon under shopping cart price rules, everything works fine.

[anusha_das]

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