(4) When the IRS asserts the 20% & 6662 accuracy- related penalty against your client in connection with some disallowed deduction, of what significance (if any) is it that the subject deduction was supported by 1. a "reasonable basis" tax opinion prepared by you? 2. a "substantial authority" tax opinion prepared by you? 3. a "more likely than not" tax opinion prepared by you? (As to each of these three scenarios, your opinion did of course reflect a correct analysis of the relevant tax authorities as of the date you delivered it, which was the same day on which your client's tax return was filed.)