I asked my LOR if P.C. is plural why not require 2 P.C.’s? He answered (are you sitting down?):
Although most poskin say one is enogh, indeed some hold you need TWO P.C.”s (told me Tshuvas Avrohom ben HaRambam s. 86 & s. 100 in name of his father the Rambam holds this)!
Then he told me something weirder: In Tshuvas Ma’ri Halevi (brother of Turei Zohov) s. 37 says that tow P.C.’s are enough only if the two P.C.’s are very choshov [like R’ kavevsky and R’ Shtienman], but if the P.C. are regular people – TEN are required!!
To me, that is kind of “interesting”.