Why Germany minimized six-inch damage to Graf Spee

Why was it important for Germany to deny that six-inch shells seriously damaged Graf Spee?

It was a prestige issue: Germany preferred to attribute the damage to a heavy cruiser rather than admit that light cruisers had helped disable a major national warship.

Graf Spee carried national status as one of Germany's most important interwar warships. Assigning damage to Exeter's eight-inch guns preserved a more flattering story than acknowledging that Ajax and Achilles had inflicted meaningful harm with lighter weapons.