I played Liberation Day and The Outlaws on brutal difficulty and completed the bonus objectives to get a total of 100,000 credits.
Then I completed Zero Hour on brutal but did not complete the bonus mission, so I did not get any credits.
I replayed Zero Hour on casual difficulty and completed the bonus objectives. The game ended and told me I had earned 55,000 credits on the summary screen however back on Horner's Battle Cruiser, it says I still only have 100,000 credits.
Why do I not have 155,000 credits now?