Dingbat Corporation has issued $140 million of 4.5%, 10-year callable bonds at par. For the first eight years, interest rates on comparable debt increases to 7%. However, at the start of the 9th year, interest rates fall to 3.0%. The call premium is equivalent to a one year coupon. Briefly explain why Dingbat should or should not implement a refundng operation, ignoring brokerage costs to issue or redeem.