[BTS] Units ArtDefineTag and game era

I have been using the Varietas Delectat for some time now, which as many of you surely know creates many different UnitArtStyleTypeInfo for each different civilization, and also introduces a new Future Era in CIV4EraInfos.xml with new 'glassy' and modern city and buildings artstyles.

But it also seems to introduce a problem due to the combination of the above. In regular civ, units can have an early, middle and late ArtDefineTag, and these progress every two game eras: Stone and Classical ages use the early tag, Middle and Renaissance ages use the middle tag, and Industrial and Modern ages use the late tag.

With the addition of the Future era in VD, this seems to no longer be the case. Industrial age uses the middle tag, and thus the late tag appears as late as the Modern age. This causes great generals to still carry chainmail, sword and shield in an age of factories and machine guns, and workers to dress as middle ages peasants, among other possible things.

I was wondering why does this happen and how could this behavior of the game be altered, so that I could correct it and control which eras will use which ArtDefineTag for the units. I already looked in CVInfos.cpp, which apparently is where the word 'ArtDefineTag' can be found, but can't really understand what is going on there.

Any help is appreciated.