Point is that not all lines are equal. The 30% that the tool didn't make are the hard stuff. Not just in line count. Once an approach or an architecture or a design are clear then implementing is merely manual labor. Progress is not linear.
You shouldn't judge your sw eng employees by lines of code either. Those that think the hard stuff often don't have that many lines of code checked in. But it's those people that are the key to your success.
I don't think any reasonable person is using "lines of code" as a hard metric for anything -- as you've noted, the quality and impact of code isn't proportional to its length.
Lines of code serves as a directional heuristic at best, but that's ok.
You shouldn't judge your sw eng employees by lines of code either. Those that think the hard stuff often don't have that many lines of code checked in. But it's those people that are the key to your success.