Your story brought to mind this bit of Apple folklore[0], wherein Bill Atkinson, the author of QuickDraw, reported his weekly LOC as -2,000 after implementing optimizations.
That's pretty common, my contribution to my current work is surely in the negative as well due to the massive amount of spaghetti code I had to refactor.
[0] https://www.folklore.org/StoryView.py?story=Negative_2000_Li...