As a retired bureaucrat, my interpretation is that the BATFE management is doing this as a desperate self-protective measure.
With the discovery of the ATF manual that took out the exception for M855 and SS109 ammunition before they made the announcement, the ATF management understood that it was hanging way out in the wind, with very little protection or support. The digital trail would show that they approved of the ban before there was any public comment or due process.
There is the little matter of Hillery’s emails... Giving the ATF management grave concern that a congressional committee might actually follow the digital and email trail of who approved of the modifications to the manual.
They have seen that President Obama is willing to kick almost anyone under the bus if it is convenient for him...
In my humble opinion, this announcement is an attempt, which will likely be successful, to short circuit any investigation.
That sounds like a reasonable and logical assumption. I truly find it difficult to believe that the BATF gives a rats ass about 80,000 people who object their fascist rulemaking.