OP here. Yep - the record keeping is out of this world. Due to the spending clauses of the Constitution, even a penny spent in excess of budget or even without all the proper authorities in place can result in a Constitutional violation, and you need to write a fulsome report to your agency head, Congress, the White House, auditors, etc. I've seen it done for what are effectively rounding errors for the US Govt (a few hundred dollars in the wrong spending 'bucket').

Echoing comments above, the laws/regs are strong, the problem continues to be implementation. Govt fiscal IT systems are some of our worst / most tricky legacy systems to modernize.