Basic accounting isn't exactly rocket science.
But one beyond the bureaucrats apparently... No bucks, no Buck Rogers. The truly scary part is that there was a $2 billion gap between the money NASA thought it had, and what was really in the accounts. Which direction do you suppose the error lay, up (to the good) or down (to the bad)? I assume, as with most people who can't balance their checking accounts, that it was negative.... Hence, a whole bunch of NASA checks likely are set to bounce...