Hello! My name is John, I will work diligently to provide accurate advice and information.
Indeed, the end user can only use the "deauthorize all" feature once in any 365 day period.
However, you can deauthorize each computer individually without limitation I believe.
On each computer, open iTunes;
Click the "Store" menu item
*Note: If running iTunes 11 on Windows, you may need to show the menubar
Then, click "Deauthorize this computer...".
If you do not have access to all the computers you would like to remove, you will need to contact a special dept of iTunes Support via the Express Lane service to have them manually do it for you.https://expresslane.apple.com/Issues.action
Choose the correct category and issue as prompted by the service above and you will eventually reach a web form where Apple promises to respond within 24 hours.
As an alternative, if you do not wish to handle it online, you can try calling this number: 1-800-676-2775. Ask if they can verify you as the owner of the account for the purposes of deauthorizing computers in iTunes and explain your situation.If you continue to have questions on this topic, just reply back to this discussion. I will be more than happy to work with you further. Hopefully, this info will answer your question
. If so please, please remember that when you are asked to give a rating, you are rating my personal service only and not this website itself or your issue.
Thanks and good luck,