Bear in mind that a 300 bar DIN fitting has more threads on a deeper valve and regulator than a 232 bar version. This is to handle the extra pressure.
It allows 300 bar kit to fit to a 232 bar cylinder valve which is safe but 232 bar DIN fittings will run out of thread before the O ring seals on the cylinder valve. This avoids 300 bar being applied to 232 rated equipment.