Question on AP

I used AP to enter USA while coming back from India trip last week. While I was in India, my H1B extension petition got approved. Now I want to get H1B stamping done in Mexico. On US consulate website, it shows following note: Applicants who entered the U.S. with one visa category and are seeking to return to the U.S. with a different visa category cannot apply for a visa at a Consular Section in Canada or Mexico.
My question is: Is entering on AP considered separate visa category? Just want to make sure I can go to Mexico/canada for visa stamping.
Please move to appropriate thread once answered.