Post-completion OPT: You may apply to participate in post-completion OPT after completing your studies. If you are authorized for post-completion OPT, you may work part time (20 hours or less per week) or full time.
链接:https://www.uscis.gov/opt
括号里面的表述本来是at least 20 hours per week, 而现在变成了20 hours or less per week。