Paper 1040-X (for 2023) mailed to Austin:  February 10

Notice 21-B and Refund Check mailed by IRS:  April 10.

Tax decrease of about $19,000 and interest of about $2,100. 

Error on original return was made by a CPA who didn't ask enough questions to determine basis of real estate sold (inherited in 2020, but used 2004 purchase price).