Question about early and late Japanese WWII colors

I'm quite ignorant about Japanese tanks and colors, so I would like to ask for help with this subject.

I'm a little confused about the subject of early and late colors, and I tried to search but couldn't find information about it. The thing is, I got both sets of Gunze Mr. Color lacquers, and according to the boxes the early colors were used until the year 18 of the Showa period and the late ones from year 19, which I think are equivalent to 1943 and 1944. However, when comparing the instructions of both Tamiya and Fine Molds Type 97 Shinhoto Chi-Ha, all the markings for the Tamiya one are in the new colors, and in the Fine Molds they're all in the old colors (except one homeland defense example), even ones as late as Luzon, and they cover pretty much the same period as the Tamiya examples. I think it's likely that in Saipan there might have been tanks in the old scheme, but also in Luzon? They didn't repaint their tanks to the new scheme?

Also I think I read somewhere that before they changed the scheme, they had discontinued the yellow lines in the tank, but still the Fine Mold markings, even the very late ones, are shown as with that line. If the old scheme really lasted that long, should these lines still be there? One last thing is that for the early turret Chi-Ha, in the Tamiya instructions they don't specify any particular color for the mantlet and main gun, but in the Fine Molds early ones it's shown to be painted a khaki color. Is this correct?

The reason for all of this is that I'm currently building a Shinhoto Chi-Ha plus a Type 1 Ho-Ni, and I'm not sure which schemes to use. I intend to paint the Ho-Ni as one from the Battle of Luzon (though it seems I don't have many options anyways), and not sure yet about the Chi-Ha, but maybe one in Saipan. So I would like to know if they should be in the old or the new schemes.