Your questions are welcome.
You have just officially successfully made me confused..
But thanks for your input, now my level of knowledge in grammar has just increased by a level..
Since I'm living in Indonesia, and the method that I've been using in tutoring is the one that I shared in the post, I think I'll stick to the old rule (verb agrees to the closest subject), or was it the new one?
I don't even remember which one is which.
Because I don't want to cause any confusion to my students (like you just did to me)