Round Discount Value With PHP_ROUND_HALF_DOWN

Round the discount value using PHP's PHP_ROUND_HALF_DOWN method.

add_filter('advanced_woo_discount_rules_discount_prices_of_product', function ($discount_prices, $product, $quantity, $cart_item){
    //FOR CHANGING DISCOUNTED_PRICE you can change it in $discount_prices['discounted_price']
    if(isset($discount_prices['discounted_price'])){
        $discount_prices['discounted_price'] = round($discount_prices['discounted_price'], 0, PHP_ROUND_HALF_DOWN);
    }
    if(isset($discount_prices['discount_lines'])){
        foreach ($discount_prices['discount_lines'] as $key => $value){
            if($key !== 'non_applied'){
                $line_discount = $discount_prices['discount_lines'][$key]['discounted_price'];
                $discount_prices['discount_lines'][$key]['discounted_price'] = round($line_discount, 0, PHP_ROUND_HALF_DOWN);
            }
        }
    }
    return $discount_prices;
}, 10, 4);