“kashrus agencies rely on many kulos that you would never use in your home”
This is false.
You are mistaken, in fact the opposite is more correct.
It most likely depends on the individual. For someone who is makpid on cholov yisroel, or pas yisroel, or hashgocha temidis on tuna (or salmon), or bishul yisroel on potato chips, or worms in fish, or non – surgical cows for milk, or heter mechira on Israeli produce, or oil produced in a plant not used for animal fats, or “chassidishe” shechita, or (need I continue?)…
some the national hechsherim would definitely use kulos that he or she would not.