Problems tagging .m4b files

I have searched but cant find an answer to this.
I have been having problems with tagging m4b and maybe m4a files
the largest and first problem i run into is with auto numbering
it will sometime only tag some of the files (with their correct #) while at other files none are tagged.

I have tried removing all tags and starting over, tried playing around with mpeg option settings
not just auto numbering either
have tried changing the track in the sidebar and saving, nothing
have to change it in explorer properties for it to work and then it does not even show up in mp3tag
not just those files either, happens with a lot of different files.
any ideas?

I can only guess: if some files work and others don't: what about access rights?
What about digital property rights?
What kind of tags do you read with MP3tag? Only V2.3 or V1? That would be good.

they are not protected or anything,
honestly i dont know much about tags, just enough so they show up right in whatever program i am using
but as i said i have tried playing around with the settings and it doesnt seem to make a difference
right now they are set
read: ID3v1+v2
write: ID3v2 -ID3v2.3 UTF-16
remove: all

2 Questions ?

Can you play them in iTunes ?
Can you change the info in iTunes ?

yes there is never any problems playing them
and yes, as in explorer, i can change them in itunes, but doing that way kind of defeats the purpose of mp3tag

I have a similar problem. I just tried to tag a pair of m4b files and couldn't. Checked permissions, I am the owner and have full control; they play fine, etc.

m4b files with chapters in them are apparently currently not supported.