Dear aso,
Without taking a look at your application, I cannot really help you. But if you are applying for a PhD the data regarding your higher education entrance qualification has only statistical significance. So if there is a mistake in that data, it does not matter at all for your application, so you could leave it as it is. If you want to clear up the matter further, please send us a message by the following form and give us your application number, then we can take a look at it:
https://www.uni-hamburg.de/en/campuscen ... enter.html But as I said, it is not really necessary.
Best regards,
Birte Schelling