How did you grind the credits?
Just picking the best passenger transport missions and some cargo missions, but my credit balance would be a lot more if I didn't keep doing the charity donations (which give a bigger rank boost than the data missions or passenger transport),
When I go to get that cutter tonight (after the final Duke rank achieved) I'll buy it with a 15% discount in Li Yong Rui space, plus elite rank 5% discount on top of that, and so overall the cutter will basically have been free
Then next week I can start all over in a golden sidey.