Is the armament revised to counter a misconception about Hayabusa fitments? The early ones had twin Ho-103 guns, some in the South Pacific started replacing one for a surplus Type-89 due to a shortage of ammunition in the face of the Allied campaign against merchant shipping (plenty of 7.7mm was available but not much 12.7mm for the Army). By this time the early model Hayabusa were being used only as second echelon, mostly as a tactical scout or fighter-bomber. By 1944 only a few remained in training and scout units and most of these fitted with two Type-89 scavenged from other obsolete models.
So armament progression actually goes in reverse to popular misconception for the Hayabusa Type I, starts with twin 12.7mm in 1941, goes to one 12.7mm and one 7.7mm in late-42 when it is a reserve fighter and by late-43 has two 7.7mm and is only a scout.
RAAF speculators tested a rebuilt Hayabusa in late 43 (Type II I think) and concluded that the twin Ho-103 is actually a surprisingly effective armament, they didn't rate it as any less capable of shooting down planes than typical fighter conventions like the Hawk and its bank of .30's and .50's. The Japanese made explosive small rounds better than the Italians did, so their Ho-103 was a little more dangerous than the heavy Scotti or Breda despite using the same ammunition dimensions.