ORIGINAL: mind_messing
- I'd absolutely not support shutting down Oscar production. Most of the IJA fighter strength use Nates, and the Oscar is a significantly better airframe than the Nate. More importantly, the Oscar needs to tide you over till the Tojo or other mid-war IJA airframes.
I wouldn't dedicate more than two factories to Oscar production, like I said. 60 Oscars / month after February 1942 is ample, IMO. True, the Nate is in dire need of replacement, but scenario 2 availability of Oscar Ia, Ib and Ic aircraft (including reserves) can provide that buffer. Don't forget to switch all home islands Oscars to Nates for your training groups. Nates can still serve for a time in China if opposition is minimal.
With scenario 2 expediting of Ki-44-IIa production, you can be in Tojo clover on May 1, 1942. As the Oscar-IIa doesn't come online until August 1942, I'd rather focus on my fighter backbone for my IJAAF in mid-1942-1943. And that's not going to be the Oscar. I still will produce the Oscar IIa, IIb and so on as capable long-distance escort and (later) kamikazes.