Steven is a CPA who fails to include rental income on a tax return he completed for a client. The omitted rental income was from a new rental property purchased by the client this year and therefore had not been reported on prior years' tax returns. The client did not mention the new rental property to Steven in any communications with him. Has Steven exercised due diligence under Circular 230 10.22? Would the answer change if he also kept the rental income records for the new rental property and still omitted the income from the tax return?