Tax Rules is not working for Item / Item Group

Dear community,

I am testing Tax Rule. My goal is, for my Sales Order, if I select a line items with item group = “Services” (a service item), then, the Sales Taxes and Charges should be set to “Sales Service Tax”.

So, I create a Tax Rule as following,

But when I create Sales Order, the line items selection does not seem to trigger the Sales Taxes and Charges template.

I also check into the code for function tax_rule.get_tax_template(), it also seem that, the Item and Item Group are not taking into account.

On other field like, Customer, Customer Group, City, the rule works fine. So it seem like, only header fields is being used.

I am wondering if this is an unfinished features, a bug or I just misunderstand it some how.

Anyone has experiences the same?

Thanks,

Note: I also try to use Item Tax Template, but I think it can’t be for my case because it can’t differentiate Sales / Purchase type, like Tax Rule does.