I do not speak German.
I searched the answer is the numerals in German is like this : 6,15 45;653,68 (6.15 45,653.68)
If so, I think your algorithm should be right.
I made a demo here and you may check it if it is right.
To make the date in your format I know 2 ways：
1. Manually specify each variable
2. web/settings.js file DATE_FORMAT='yyyy-mm-dd';
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