I tried to import data for the account.invoice model with correct invoice_line_ids/invoice_line_tax_ids/id and invoice_line_ids/price_unit.
Data correctly reflects in account_invoice_line and account_invoice_line_tax, but account_invoice has a zero value for amount_tax.
I tried to force import using amount_untaxed, amount_tax, amount_total, but these fields are ignored by Odoo import.
I have been able to import Quotations/Sales Orders