Hi
I'm playing as the Terran Alliance and I've noticed that my credit balance is unaffected anytime I upgrade a ship(s). however I can only upgrade ships with a upgrade I can afford.
For example if I have 1000 credits I can upgrade as many ships as I want with any upgrade that costs 1000 credits or less. I can do this any many times as I want in a turn (every turn if I like )with out ever reducing my balance of 1000 credits
thanks