Yes, we're all under disaster; that's why the filing date is delayed.

"It was at $10000+ refund      and @qbteachmt   yes I keep up on the IRS news"

The links I gave include the various computations and rates that were used: Interest is paid at the legally prescribed rate that is adjusted quarterly. The rate for noncorporate taxpayers for the second quarter, which ended June 30, 2020, was 5%, compounded daily. Effective July 1, 2020 the rate for the third quarter dropped to 3%, compounded daily.

"I didn't think the interest was added unless it was efiled/accepted after April 15th"

Refund Date. Not filing date.

"No interest will be paid for any refund issued before the original April 15 due date."

"The average amount of the interest payments is $18.

Individual taxpayers who filed a 2019 return by the July 15, 2020 postponed filing deadline and have already received a refund will receive an interest payment separately."