广州H1b首签五周后邮件询问说additional AP

11月初广州首签H1b，水check，发了绿色221g条，说4 周。
现在五周多了没任何动静，还停留在面签当天。
发邮件询问，说是‘...it is undergoing additional administrative processing. This processing cannot be waived, ... At this time, consular officers are advising applicants that this processing may average around 4-5 weeks...'

additional administrative processing 是啥意思啊，让我再等四五周吗