That roman numeral has actually much more meaning than the fancy number on the icon.
It also tells AI which component in the family is better. This explains that late game design quirk. I changed those numerals on all engines so that the ion engines are 1-3, contra terrene engines 4-6, jacketed photon engines 7-9 and quantum engines 10-12.
Guess what, as soon as AI researched new engines all designs using engines were updated. No longer were those old colony ships stuck with the same old ion engine 3's.
Yippee!!!
