I was recently told that in addition to counting the eleven marks of incense with one's fingers during prayer, as is customary, some also count the six instances of the word "sammim" in the verse "ויאמרהאלמשהקחלךסמיםנטףושחלתוחלבנהסמיםולבנהזכה".
What is the reasoning behind or source for this additional finger-counting? Is it indeed acceptable according to the teachings of the Ari z”l, as I was told?