Yes, that is correct.

You may want to go into each Client record and *check* the "Taxable Time Entries" and/or "Taxable Expenses" if either or both of those are taxable. That way when you create the Time and/or Expense entries, they will automatically be checked (or not) when you create the record. You can also assign the specific tax in each client too. Just in case you have clients in different tax jurisdictions, you can set the proper tax fields for each client. Hope that makes sense?