Thanks to Douglas Gibson who alerted me to this 2017 paper posted on Aulis.com:
Lunar Laser Ranging: A Review – by Andreas Märki Master of Science of the Swiss Federal Institute of Technology 8703 Erlenbach ZH, Switzerland a.m.maerki@bluewin.c…
The paper contains quite a few technical details and equations… and concludes:
“In Murphy_2007 [11] §8 a “possible degradation of lunar reflectors” is mentioned. According to the number of return photons I go even further and conclude that in all lunar laser ranging experiments the measurements were taken to the bare surface of the Moon.”
