I cant combine Expendable Ground Main Defence and imerialst ?

Hello,

i just bought Expendable Ground Main Defence improvment, and when i chose imperialist tactics, main ground defence units are not -10 cheaper. They cost the same as before with just imperialist tactics. How is it possible ?

It may take some time for atwar to recognize that you bought the upgrade. I bought both imp and EGMD, and inf now cost only 30 instead of 40, so it works for me. It might take a day or two or something for atwar to make the upgrade work