Need little clarification about GetAllDiscountsAsync method nop4.5.x

//we load all discounts, and filter them using "discountType" parameter later (in memory)
            //we do it because we know that this method is invoked several times per HTTP request with distinct "discountType" parameter
            //that's why let's access the database only once
            var discounts = (await _discountRepository.GetAllAsync(query =>
            {
                if (!showHidden)
                    query = query.Where(discount =>
                        (!discount.StartDateUtc.HasValue || discount.StartDateUtc <= DateTime.UtcNow) &&
                        (!discount.EndDateUtc.HasValue || discount.EndDateUtc >= DateTime.UtcNow));

                //filter by coupon code
                if (!string.IsNullOrEmpty(couponCode))
                    query = query.Where(discount => discount.CouponCode == couponCode);

                //filter by name
                if (!string.IsNullOrEmpty(discountName))
                    query = query.Where(discount => discount.Name.Contains(discountName));

                query = query.OrderBy(discount => discount.Name).ThenBy(discount => discount.Id);

                return query;
            }, cache => cache.PrepareKeyForDefaultCache(NopDiscountDefaults.DiscountAllCacheKey, 
                showHidden, couponCode ?? string.Empty, discountName ?? string.Empty)))
            .AsQueryable();

var query = _discountRepository.Table;
            if (!showHidden)
                query = query.Where(discount =>
                    (!discount.StartDateUtc.HasValue || discount.StartDateUtc <= DateTime.UtcNow) &&
                    (!discount.EndDateUtc.HasValue || discount.EndDateUtc >= DateTime.UtcNow));

            //filter by coupon code
            if (!string.IsNullOrEmpty(couponCode))
                query = query.Where(discount => discount.CouponCode == couponCode);

            //filter by name
            if (!string.IsNullOrEmpty(discountName))
                query = query.Where(discount => discount.Name.Contains(discountName));


            if (discountStatusId.HasValue)
            {
                query = query.Where(x => x.Active == discountStatusId.Value);
            }

            //we know that this method is usually invoked multiple times
            //that's why we filter discounts by type and dates on the application layer

            if (discountType.HasValue)
            {
                query = query.Where(discount => discount.DiscountTypeId == (int)discountType.Value);
            }

            //filter coupin code
            if (requiredCouponCodeOnly)
            {
                query = query.Where(x => x.RequiresCouponCode);
            }

            //filter by dates
            if (startDateUtc.HasValue)
                query = query.Where(discount =>
                    !discount.StartDateUtc.HasValue || discount.StartDateUtc >= startDateUtc.Value);
            if (endDateUtc.HasValue)
                query = query.Where(discount =>
                    !discount.EndDateUtc.HasValue || discount.EndDateUtc <= endDateUtc.Value);

            //hide archived
            if (hideArchived)
            {
                query = query.Where(x => !x.Archived);
            }


            if (discountType == null)
            {
                query = query.OrderBy(discount => discount.Name).ThenBy(discount => discount.Id);
                query = query.OrderByDescending(d => d.Id);

                var cacheKey = _staticCacheManager.PrepareKeyForDefaultCache(NopDiscountDefaults.DiscountAllCacheKey,
                     showHidden, couponCode ?? string.Empty, discountName ?? string.Empty);

                var activeDiscount = await _cacheManager.GetAsync(cacheKey, async () =>
                {
                    return await query.ToListAsync();
                });

                return activeDiscount;
            }
            else
            {
                query = query.OrderBy(discount => discount.Name).ThenBy(discount => discount.Id);
                query = query.OrderByDescending(d => d.Id);


                var cacheKey = _staticCacheManager.PrepareKeyForDefaultCache(NopDiscountDefaults.DiscountAllCacheKeyByType,
                    showHidden, couponCode ?? string.Empty, discountName ?? string.Empty, discountType.Value);

                var activeDiscount = await _cacheManager.GetAsync(cacheKey, async () =>
                {
                    return await query.ToListAsync();
                });

                return activeDiscount;
            }

                var cacheKey = _staticCacheManager.PrepareKeyForDefaultCache(NopDiscountDefaults.DiscountAllCacheKeyByType,
                    showHidden, couponCode ?? string.Empty, discountName ?? string.Empty, discountType.Value);