The posts upthread show that pfennigs were being produced continuously in Saxony in the second half of the 17th century. The same was true of dreiers and 1 groschen coins.
In the PLC, on the other hand, in the reign before Frederick (Sobieski 1676-1696), the smallest silver coin produced in significant quantity at the royal mints in Krakow and Bydgoszcz was the szostak which contained 1.2 grams of fine silver. Small change had not been produced in Polish mints since the early 1660s, and small change containing silver even earlier.
Frederick decided to not use the Polish mints used previously, but to supply the coinage needs of the PLC from the Dresden and Leipzig mints.
As shown earlier, he had coins produced with the legend MONETA SAXONICA which presumably were intended for circulation in Saxony.
,Would it not make sense that the coins with the prominent Polish-Lithuanian coat of arms on them have been intended to supply the small change needs of the PLC, which had more than 5 times the population of Saxony? Rather than circulate in Saxony where people would have expected their coins to have the Saxony coat of arms?