Not sure if it was an official "quota", however DPE's who pass rate was higher than some statistical norm, were looked at much closer. How do I know? When I got back to flying I googled the DPE who gave me my private 25 years ago. Seems he was involved in a lawsuit against the FAA for unlawful termination. Based on the reading online, he would give a check ride and sometimes, if the student passed, he would send in the paperwork saying they failed the first time and passed on the re-take, this kept his pass stats in-line (at least he didnt actually FAIL the student to do the same), it was found out when some of these students went to apply to airline jobs and were asked if they had failed any check rides. I believe the lawsuit was dismissed however I think he is still working for the FAA in some other capacity (so maybe some sort of settlement)