I'm fascinated: does your company/manager truly track SLOC and promote based on that?
Or is SLOC here more of a proxy for "features shipped"?
Because if this is what's happening, I'd encourage two changes:
1. Communicate differently to HR, lead, and skip - either use different approaches of documentation, or point out different aspects of your contributions
2. If trying various different approaches don't work... leave.
For communicating differently - I used to work at a large company, and our yearly reviews had places to capture accomplishments. That was a broad topic: it wasn't just features built, bugs fixed or identified, etc. It would also be totally appropriate to put ways you saved money or time on various initiatives, and I would frequently put down items like this.
How do you communicate "how good" your "communication, soft skills, and team work have been this year"?