Hello, after my investigation I found the following:

the tax is calculated here - *TaxAuthorityService.rateProductTaxCalc* * * Firstly there is a loop through all product items: for (int i = 0; i < itemProductList.size(); i++) { GenericValue product = (GenericValue) itemProductList.get(i); BigDecimal itemAmount = (BigDecimal) itemAmountList.get(i); BigDecimal itemPrice = (BigDecimal) itemPriceList.get(i); BigDecimal shippingAmount = (BigDecimal) *itemShippingList* .get(i); List taxList = null; if (shippingAddress != null) { taxList = getTaxAdjustments(delegator, product, productStore, payToPartyId, billToPartyId, taxAuthoritySet, itemPrice, itemAmount, *shippingAmount*, ZERO_BASE); } // this is an add and not an addAll because we want a List of Lists of GenericValues, one List of Adjustments per item *itemAdjustments*.add(taxList); }

The *itemShippingList *contains 0 amount per any product item in any case, because of *Map serviceContext = this.makeTaxContext(i, shipAddress, shoppingCartItemIndexMap);* where product.add(i, cartItem.getProduct()); amount.add(i, cartItem.getItemSubTotal(itemInfo.quantity)); price.add(i, cartItem.getBasePrice()); * shipAmt.add(i, BigDecimal.ZERO); // no per item shipping yet* shoppingCartItemIndexMap.put(Integer.valueOf(i), cartItem);

and I do not see any sense in shipping amount per product item, because I have shipping amount per shipping group.

So, secondly: there is another possible way to add the shipping tax

if (orderShippingAmount != null && orderShippingAmount.compareTo(BigDecimal.ZERO) > 0) { List taxList = getTaxAdjustments(delegator, *null*, productStore, payToPartyId, billToPartyId, taxAuthoritySet, ZERO_BASE, ZERO_BASE, orderShippingAmount, ZERO_BASE); orderAdjustments.addAll(taxList); }

and orderShippingAmount has value in my case (9 EUR), let's go to the getTaxAdjustments (notice that product specified as null, because this call does not relate to any product) getTaxAdjustments tries to get all necessary TaxAuthorityRateProduct to calc the tax,

*List lookupList = delegator.findList("TaxAuthorityRateProduct", mainCondition, null, orderList, null, false);* * List filteredList = EntityUtil.filterByDate(lookupList, true);* * * * if (filteredList.size() == 0) {* * Debug.logWarning("In TaxAuthority Product Rate no records were found for condition:" + mainCondition.toString(), module);* * return adjustments;* * }*

but in the case of the product == null, the following is used productCategoryCond = EntityCondition.makeCondition("productCategoryId", EntityOperator.EQUALS, null);

and that I do not understand. It tries to find TaxAuthorityRateProduct to calc the tax , which are not assigned on any product category. Could you help me to understand the idea of this calculation? Why the ordering shipping amount depends on TaxAuthorityRateProduct . To have a TaxAuthorityRateProduct without Category specified is illegal and it is not possible to add it do via UI.

Thank you.