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There is a method for going back and trying to change a determination of separation. You'd have to file a DD Form 149 with the records corrections board, alleging that not giving you a medical discharge was an error or an injustice.
Now, there are numerous problems with doing so. First, you're beyond the normal 3 year rule they have (meaning 3 years from the date of the issue). They waive this often, but they don't have to and that could get your claim removed without consideration. Second, it's extremely difficult to prove error or injustice in a discretionary command function. They don't have to medically retire people. They can, but they don't have to. As it is discretionary, it's difficult to prove error. Finally, there really is no utility in doing so. Right now, you have 100% disability from the VA. If you were to go back and get your separation changed to a medical retirement (and that's all you can get....you can't get a regular retirement), you'd not get any increase in income. You'd have to waive whatever percentage of your VA to get the medical retirement. Both are tax exempt, so you gain nothing by the distinction. You can't qualify for the concurrent receipt (getting both is only possible when you completed a full 20 year retirement and you get VA disability too....then you can receive both). So, in terms of financial gain, there will not be any.
The point here is that this would be a very difficult task, as it can take up to a year to do, and there would be little to no gain from doing so.
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