Sorry for delay in this answer, dear Philipos.
I was looking for a e-book but from Mexico the download is impossible. I use a proxy to get access to such volume.
In the first pages, the Dedicatory indicates that this is a 'posthumous' volume, done under the general plan/idea of the work started by Mai, trying to accomplish the incomplete tasks.
By this reason, the date of publishing is very late -1871, around 20 years after the first imprint-, and was realized by Josephus Cozza, who seems to be working in some of the earliest editions of the Vatican Codex
, around the 1868 year.
I'm trying to update the NPB adding this late volume, which is by itself, a great and magnificent notice.