Actually.... you are mixing Victoria I with Victoria II. I am well aware that Victora I works as you said but Victoria II doesn`t.Yes I am sure. It only affects anyone in your nation. Every other nation is not affected by your tariff setting. It is how the world market works. There is no trading between nations. only that big blob of the world market where every excess good get dumped into after the common markets got processed.
So sadly only your own POP's and industry are affected. Not even your SOI uses your tariffs.
I even looked up the manual for Viky 2 - http://wizzywizzyweb.gmgcdn.com/media/products/victoria-ii/manual/victoria-ii_manual.pdf , page 49 , tarrifs affect goods sold and bought from the world market, yes the world market exists.