GST code used on the Deposit account
If you need to have multiple GST codes when collecting deposits from customer or made advance payments to a supplier, then you are required to have multiple deposit received accounts (current liabilities account type) and advance payment accounts (current assets account type).
Create the account with the relevant GST code (select the GST code from the Tax Code field), such as a G GST code for the "Advance Payment to Supplier (G)" account. Next, create multiple Deposit item (one Deposit item for each GST code) and link it to the relevant accounts. Example, you may create a deposit item, Deposit_G, and link the “Advance Payment to Supplier (G)” account at the “Expense Account when buying” field and “Deposit Received from Customer (G)” account at the “Income Account when Selling” field.
So when process the order with a deposit paid or collected at the Sales Order or the Purchase Order transaction. The correct GST code will be used for the payment or receipt transaction.