I am still trying to figure out how IRS figured the penalty on a 2020 return.  Does anyone remember, was the 90% requirement relaxed last year?  Here are the numbers:

Tax on return $ 12,192

Withholding  $5,297

RRC (was allowed)  $1,200

Balance due $ 5,695

Return was filed June 7, 21 days after the May 17 due date.

IRS charged interest on the $5,695.

But they charged FTP penalty only on $3,295.  Where does that number come from?