I also want to know how should I tag subcontractors in creating expense. Is this should be in the category or item details? For example, for electrical, I have already added a "service" type of product and I associated that with electrical. And I can use that tag in the item details or is it better to use the "subcontractor" chart of account? 

What about for the transaction linked from a bank account? Sometimes, it automatically links to the expense being created and the sales tax in it is exempt but it should not be like that. Is it okay to leave it as is and use exempt in the sales tax or amend it according to the receipt?