Horowitz having approximately 470 is a number lifted directly from Sessions' March 29, 2018 letter to Grassley, Goodlatte and Gowdy. This is the letter than first publicly named Huber.
To carry out these duties, Title 5 of the United States Code provides the Inspector General with broad discretion and significant investigative powers. The office currently employs approximately 470 staff ...
Mixing Huber and Horowitz is a common mistake, I've posted an error of that nature at least once, just in a hurry. It is also natural to conflate Horowitz and Huber from the way this particular letter is phrased, with subjects mixed tightly in the prose.
But it is also fair to think that if Huber is teamed with Horowitz, Huber shares or has access to Horowitz's staff, and in a way then, has the same 470 that Horowitz has.
Just saying, attributing 470 to Huber is not much of an error, and to me, is not "pulled out of thin air."
It’s an approximate number... it could have been a tell regarding the 4-70th MI brigade.