This was discovered during the 4.7.0 testing. The 4.7.0 LIDAR sims were taking longer than when run with 4.6.x. After some investigation, it was discovered that the radiometry solver for the atmospheric backscatter returns was never configured to run.
** It should be noted that these returns a very small for most scenarios.
We discovered that the code to enable the calculations had been disable for the entire 4.6.x release cycle.
Fixed for the 4.7.x release cycle.