AA Weapons
If this is correct then total IJA light flak production from 1938 to 1945 was only about 3,000 weapons. Furthermore 80% of IJA light flak had a ROF of only 300 rounds per minute. The numbers aren't even close compared to the Heer. Furthermore German army light flak was qualitatively superior for the most part.
I don't doubt that F4U pilots considered IJA flak to be dangerous. But Typhoon and P-47 fighter-bombers faced German flak that was much worse. So it would not be fair to compare loss rates to ground fire between CAS aircraft that fought in Europe and those that fought in the Pacific.