Why is reading ISRC so difficult? Options

[imazed]

This is my first post so apologies if it is not in the right place.
I plan to convert totally to digital replay keeping all my files on a media server and using a dedicated quiet PC for playback - nothing unusual about that.
I wanted to ensure that when I rip my CD collection I only do it once, that the audio is bit perfect, and the metadata is as compete and informative as possible.
I have spent a lot of time trying various ripping programs, validating metadata against Freedb, MusicBrainz, GD3 and I am now at the stage I can proceed with ripping my music collection EXCEPT that it seems to be almost impossible to get a reliable method of reading and storing the ISRC.
I have tried EAC, DBPoweramp, J rivers, MBRipper and Cuetools.
I have some CDS which will always give a valid ISRC, seven out of twelve, and the remaining five which I am unable to read. This is with any of the programs, any of three different drives, and two computers one running XP and one Windows 7. I repeat results are entirely consistent either ISRC is always there or it is never there.

YES, I do realise the seemingly obvious conclusion is that no ISRC exists but these are mainstream CDs by popular artists from labels like EMI and Columbia. As the entire music industry is paranoid about collecting royalties and the main identifier of who is playing on any track is linked to the ISRC I do not believe that the "obvious" conclusion is correct.
Interestingly the wikipedia article on the Red Book standard states:
The basic specifications state that

Maximum playing time is 79.8 minutes[5]
Minimum duration for a track is 4 seconds (including 2-second pause)
Maximum number of tracks is 99
Maximum number of index points (subdivisions of a track) is 99 with no maximum time limit
International Standard Recording Code (ISRC) should be included

If this is right then ANY compliant CD must have an ISRC encoded on each track.

On scouring this and other audio forums there are four alleged reasons why the ISRC cannot be read and these are:
1 - Your drive cannot read them - well if that was the case I would not see any of them.
2 - You have not set up the ripping program correctly - same response as point one.
3 - The ISRC does not exist on the tracks - I have no evidence to the contrary other than that previously stated.
4 - The ISRC cannot be transferred to the metadata and can only be seen in a cue sheet - I have tried writing Cue sheets and get identical results 7 out of 12 work.

The ISRC website states:
In the case of Compact Discs the ISRCs and other PQ-data are encoded in the disc sub-code (Q channel) in the disc mastering process. For this reason, ISRCs must be encoded for each track in the Pre-Master for CD. Most commercial mastering software applications have a field dedicated for ISRC. For electronically distributed formats, the ISRC of each track should be associated with it in the metadata of the file.

Does anyone have a set-up where they can reliably read ISRC?
Is there more than one method of encoding the ISRC on the CD? My understanding is that ISRC is 12 digits, case insensitive and is the first thing in the Q channel.
Is there any explanation as to why some codes are not detected by any of the programs I have listed?

[Lazlo Nibble]

FWIW: I explicitly do a full subcode check with cdrdao on every disc I rip and include the full results in the cuesheets, including all flag settings (set/unset) and the presence/absence of UPC/EANs and ISRCs. In the roughly 1000 or so discs I've ripped with this workflow, just over 45% have ISRCs, 4% have all-zero ISRCs, and the remainder have no ISRC whatsoever.

My collection skews older, but in my experience it's unusual for a recent CD (say, post-2000) not to have ISRCs, and those where they ARE missing seem mostly to be either true indie releases (nothing I own from Italians Do It Better have them) or DJ mixes/compilations (including soundtracks in the latter category).

Weirdly, I also come across titles with Digital Copy Permitted that you wouldn't expect. The Yello remasters all have it set, for example.