On September 3, 2021, in Cargo Systems Messaging Service (CSMS) #49268401, U.S. Customs and Border Protection (CBP) issued guidance on the recent amendments to Section 301 product exclusions under 9903.88.64 to account for changes to certain statistical reporting categories. The amendment is effective July 1, 2021, but the functionality updates to allow for the exclusion acceptance were made September 7, 2021.
Details can be found in the CSMS here:
https://content.govdelivery.com/bulletins/gd/USDHSCBP-2efc6b1?wgt_ref=USDHSCBP_WIDGET_2