Old Address Book syncing with iPad via iTunes!

Question

Forgive me if I'm going over old ground but there seem to be a number of threads to do with Address Book syncing, but I haven't managed to find a definitive answer, so here goes ...
I have an iPad [3] under iOS.5.1and an OSX.6.8 quad-core i7 iMac and I sync them via iTunes.
Everything, absolutley everything, syncs just fine, Calendars, Photos, etc. etc. - except, that is, for Address Book and Contacts.
The iMac Address Book is fully up to date, yet the version on the iPad is not only an old version, but a version which hasn't been current since before the iPad was bought and first sync'd!
Bizarre!
In an attempt to correct this, I unchecked the iTunes "Info > Sync Contacts button and resync'd.
The ipad Contacts book was empty - which is what I expected.
i then checked the button again and resync'd - and the old Address Book data was resync'd!
What is clear is that the iPad's version reflects that which is in the iTunes "Selected Groups" window and not what is actually in the Address Book, so I presume that the error lies with iTunes and/or my iMac and not the ipad iteself.  The iPad is, after all, only reflecting what iTunes tells it.
So, my friends, why does iTunes not show the current Address Book indiviudal cards and Groups?
From where should it be getting it's information and how can I ensure that it does get the latest version?
If there is a rogue old copy somewhere, what could it be called and how can I find it and delete it and then, perhaps amend the default path to the correct version?
All software and apps on both devices are fully up to date at the time of posting this heartfelt crie de coure!
Any advice would be much appreciated.

Answer 1

Well, eventually I had to go to the Level 2 (or whetver they are called) AppleCare geeks to get this resolved, as the "normal" guys couldn't resolve it.
After much "try this ...", "try that ..." and "try the other ..." they narrowed the problem down to a corrupt Address Book Group header in my iMac's Address Book.
It appears impossible to find out just which of my 55 Group headers was corrupt and the only way around it was to export all Contacts individually as vCards, dlete every Group and individual card entry in the Addreess Book and reimport all the vCards - and then somewhat tediously recreate all my Groups again from scratch.
It took  around two and a half hours on the phone to AppleCare and forever to recreate the Groups, but at least it solved the problem!
Whether this helps anyone else i cannot tell, but if you have a bizarre syncing pronblem it might be worth looking at this as a solution.
But take my tip:  before embarking on this, make an entry in the Notes section of each card so that you know to which Group or Groups a card belongs because it was a feat of memory way beyond me to remeber all of them and I still have the odd orphan in there awaiting a home!