He used custom accounts in Chart of Accounts… then allocated each tax component to their custom liability account. I think this is excessive effort.
Tax Summary will be improved to handle multi-component tax codes better.
Also, no need to have one tax code for Sales and other for Purchases. I mean you can but Manager is pretty smart at figuring out which transactions are sales and which purchases so you can get away with just half of tax codes and still get the same results.