To make matters worse, Japan did not really have an FS color system, but instead the various manufacturers and shipyards each had their own versions of the colors (for example ships, particularly those built or refitted at the major shipyards of Kure, Sasebo, Maizuru, and Yokosuka, were painted in slightly different shades of gray, with the color typically matching the shipyard where the ship was last refurbished.

aircraft were in a similar situation, i.e. the green color could depend on where something was made

https://www.pmcn.de/English/Japan/Japanese Aircraft Colors.htm