Most keyboards (there are expensive exceptions) start getting problems with three keys pressed at once. The art of keyboard design is laying out the matrix in a way, that the combinations of three keys that are troublesome are combinations that do not occur in practical use. Obviously the artist that layed out your DIN keyboard considered the combinations you posted as irrelevant combinations. Your DIN keyboard might actually support other three-key-combinations that would cause trouble on the PS/2 keyboard you used earlier.
The first DIN keyboard I used as child was a no-name keyboard sold by a German PC discounter. It hat the imprint "Keyboard of excellent quality and smart design" on the box. Me and my younger brother playing PC games managed to damage the cursor left key in less than one year. So much for "excellent quality". When I pulled out that keyboard (with the non-functional cursor left key) years later because I needed it for a secondary Linux box, I found out that the matrix does not support the combination "Ctrl+Alt+F3". So much for "smart design".