Look closely at your next preliminary duty statement. As of September 25, 2010, US Customs has added a new field which serves as an indicator that an electronic invoice is required for the corresponding entry when submitted via the Automated Commercial System (ACS). This new field corrects a previous inability of CPB to notify the trade to submit the electronic invoice with the entry summary.
Now that importers and/or their agents will receive electronic notification, CBP will be taking steps to ensure that the trade complies with the submission requirements. CBP has stated that “the ports have been instructed that they are permitted to pursue liquidated damages or penalties based on the filer’s failure to timely submit documents and/or electronic invoices for entry summaries submitted after October 12, 2010.”
The official announcement is available here.