"What do you think of using a metric of function point to lines of code as a metric?"
Don't get the question.  The above ratio is -- for a given language and team -- a simple statistical fact.  And it tends toward a mean value with a small standard deviation.
There are lots of degrees of freedom: how you count function points, what language you're using, how (collectively) clever the team is.  If you don't change those things, the value stays steady.
After a few projects together, you have a solid expectation that 1200 function points will be 12,000 lines of code in your preferred language/framework/team organization.
KSloc / FP is a bare statistical observation.  Clearly, there's something else about this that's bothering you.  Could you be more specific in your question?