I've noticed the ship tailor is taking too much money when making a change (if the change actually sticks!!).
e.g. I changed pylons, the game prompted me it would cost 440 credits, but after looking at my credits in the inventory screen, the tailor charged me 5 times the amount of 2200!!
I have put in GM report and bug report on this.
I hope this gets fixed soon, as it is frustrating when a change is not sticking or being overcharged for it.