A very encouraging report.
If I remember correctly, 11 made some minor changes to functions and script trigger names. It didn't prevent you from opening the file in 10, but it was ever so slightly different. That may account for the Version 11. It will require someone with a lot more knowledge of FileMaker Internals then I to be definitive on this.
An additional note on the lines which start with "Recovering..."
There appears to be a Recovering in about half of the lines of the log. It's the terminology used to describe the creation of the value lists, custom menus, scripts, data source lists, and most other stuff.
In fact, the wording on Recovering with Field now appears to only occur when creating field catalogs for the various tables. (There appear to be 183 tables in these 28 files.)
So maybe "Recover" isn't so worrisome in the context of this conversion log.
I recalled that the file which showed 11 as the file format was not only created in FM11, but had also had access restricted to FM 11 or later. That appears to be what causes it to report out as a version 11 file.
Of course, when I went looking for this option to check it in the converted file, I couldn't even locate where the option was set. That option became obsolete after the one-way conversion to 12! Duh...
So that's making sense now, too.
Another note on the length of my Conversion Log:
1779 lines were recording the "recovering script" process for each script in the 28 files. It even logged a line for each script folder and script separator.
When added to the 1781 field indexings, and all the lines for recovery/building of value list catalogs, field catalogs, etc, it's easy to see how nearly 5000 lines got logged during conversion of a larger system.
Each file in the conversion has around 2-dozen lines devoted to Recovery and Rebuilding of various file catalogs, and some lines note that these catalogs within the files are now rewritten in a new format for FMP12 as well.