I would be surprised if USADA could slide anything in without breaching their procedures.
USADA made a statement to the effect that they only disclosed in the charges document allegations that were already in the public domain (or the SSDD evidence to use the Armstrong parlance!) They did this to protect new witnesses from possible intimidation.
That's a clever statement as it indicates the possibility of new evidence. Whether there is new evidence or not remains to be seen. Certainly the blood test anomalies that USADA mentioned could be the source of new evidence, and that could take the form of expert analysis of the blood passport figures.