This is an accurate description of the legal US grading system as of March 2, 2015 (under 7 U.S.C. 1621-1627). For anyone interested, here's a link to the official USDA guidelines (grading is ยง52.5962 on page no. 2, which is actually page 4 of the PDF):
http://www.ams.usda.gov/sites/default/files/media/MapleSyrup...