Discounts - Cumulative with other discounts

protected virtual decimal GetOrderTotalDiscount(Customer customer, decimal orderTotal, out List<DiscountForCaching> appliedDiscounts)
        {
            appliedDiscounts = new List<DiscountForCaching>();
            decimal discountAmount = decimal.Zero;
            if (_catalogSettings.IgnoreDiscounts)
                return discountAmount;

            var allDiscounts = _discountService.GetAllDiscountsForCaching(DiscountType.AssignedToOrderTotal);
            //TODO:: I think some path of logic missing there?????

            //TODO::

            var allowedDiscounts = new List<DiscountForCaching>();
            if (allDiscounts != null)
                foreach (var discount in allDiscounts)
                    if (_discountService.ValidateDiscount(discount, customer).IsValid &&
                        !allowedDiscounts.ContainsDiscount(discount))
                    {
                        allowedDiscounts.Add(discount);
                    }

            appliedDiscounts = allowedDiscounts.GetPreferredDiscount(orderTotal, out discountAmount);

            if (discountAmount < decimal.Zero)
                discountAmount = decimal.Zero;

            if (_shoppingCartSettings.RoundPricesDuringCalculation)
                discountAmount = RoundingHelper.RoundPrice(discountAmount);

            return discountAmount;
        }

            var discountForProducts = _discountService.GetAllDiscountsForCaching().Where(p => !p.IsCumulative == true &&
                                                                                        (p.DiscountType == DiscountType.AssignedToSKUProductTuple
                                                                                        || p.DiscountType == DiscountType.AssignedToSkus));