I just did the calcs and based on the 5% interest until June and the 3% interest effective July 1 (both compounded daily). The final tax refund I calculated was close to the amount I received. Looks like this was the interest then. Thanks again!
It would surely be comforting to get a notice from the IRS saying that the interest was bundled in, especially given that my return took unusually longer (3 weeks) this year to process.
