The investment balance of a firm is $4,000,000 at the beginning of a two-year period and $7,000,000 at the end. The firm makes a single contribution during the two-year interval of $1,800,000. What is the difference between the approximate annual dollar-weighted yield earned by the firm if the contribution is made after 6 months as opposed to it being made after one year? (Round your answer to four decimal places.) Difference =[ answer ]