Maybe you are correct. But, I have yet to find a pennzoil oil that states it is low ash API TC rated. All the Pennzoil marine or 2 stroke oils I have seen say TCW3.
Rereading your post, I see that you state it is in 8 oz bottles, maybe that is why I havent seen it. I have only gone by the quarts I have seen. Even searching pennzoil's website, I dont see it. Got a link to it?