Costs Account Configuration = Nature of Purchase
The Amount b.tax is broken down into a "Costs" type account. A "Costs" type account is used to attach a Nature of Purchase.
To configure this account, there are 2 possibilities:
From the Nature of Purchase sheet
Attaching a Nature of purchase to an account can be done directly from the Configuration menu > Purchases section > Natures> Nature of purchase sheet.
- Account Number Selection is Restricted to "Costs" Type Accounts
- You can add / create a new account directly from the account selection table.

From the Account Plan configuration
From the Configuration menu > Purchases section > Accounts, you can add the nature(s) of purchase attached to the "Costs" type account number.

Note: a Nature of purchase can only be attached once.
Auxiliary account and Concentration account
You can define an auxiliary account and a concentration account. For more information, click here.