3 times as much, not 3 times more

If we went to a same event and you paid $1 for the ticket while I paid $3 for the ticket, I have paid three times as much as you did but I didn't pay three times more than you did, I paid two times more than you did.  This is not 3 X 1 = 3 type of Math equation, this is English language.

So I sent my question to Prof. Kuo since he had coincidentally wrote the article- "Time to put a full stop to language mistakes" and contributed to The Straits Times.

He says he has his opinion but cannot share -_- ?