One more thing im finding as im playing, when you upgrade there is a loss ofcourse, however if you upgrade the 50prest arty, to the 2nd last one, you literally get a free upgrade because instead of being 250 its now 200.

Still why are all the arty available right off the start? Shouldnt there be progression?

Also the 7.5 cm leIG 18 can move AND attack. I tested it with the 75mm FK18 which has the same movement of 2 in the exact same situation and it was not able to fire so im assuming this is also a bug.