Adding tax to an invoice in pending billing status

I'd like to confirm that we cannot add tax to an invoice or sales order if the status is pending approval or pending billing.

We're starting to charge state taxes and during my demo to accounting there were a few existing invoices that would not calculate the taxes when I checked the Taxable box on the Accounting tab. Noticed they were in Pending Billing or Pending Approval status so presume this was the reason.

This seems to work well if creating a new invoice or sales order.

I am not finding an answer in SuiteAnswers or Help so was hoping someone in the community could confirm or point me to documentation that would confirm this assumption.