You may be mixing up the versions WMaker.
You'll note "-IIs and -IIIs" that you quote? Most of those were -IIs. The -III wasn't even worked on until the second half of 1944. Production for the first production variant (i.e. non test, non prototype) didn't start until December 1944.
Yes, I agree that the factory you mention produced a lot, but a majority of what they produced was most certainly -II models. The factory was producing Ki-43s from May 1943 until the end of the war. That gives it a ~2-year headstart to produce Ki-43-IIs before the -III came into production. At the same time, Nakajima stopped producing the -II to focus on the Ki-84 and other ventures. Overall prodution was just under 6000 for all 3 types, of which Ki-43-III production (while hard to pin down exact numbers) was the minority.
Per J Baugher:
Production began in December of 1944, most of the aircraft being built by Tachikawa Hikoki K.K..
The Ki-43-IIIa was assigned to units defending Tokyo and other major Japanese cities and was also used in numerous suicide attacks during the final phases of the Pacific War.
You can even see the photo of a Ki-43-III taking off on a kamikaze mission on wiki, where possibly you saw the line about the factory producing -IIs and -IIIs?
The Ki-43-I and Ki-43-II had a long and noted history of aerial combat. The Ki-43-III not so much. It was Ki-43-Is or Ki-43-IIs flying over Burma, not Ki-43-IIIs. You're at least a year too early for that to be remotely possible, I think. It was -Is and -IIs over Singapore.
I think you'll be hard-pressed to find much record of Ki-43-III service, if you look into it.
Just so we are clear (so we're on the same page), the Ki-43-I and Ki-43-II would be great additions and most needed additions to this game. I have always said as much. The Ki-43-III would fill almost no role in this game due to its limited service and being surpassed by better aircraft at the time. At the end of 1944 and into 1945 it was just obsolete.