Bobbi Brown Brightening Finishing Powder

I went to Sephora to buy Bobbi Brown brightening finishing powder yesterday. After I tested it in porcelain pearl and nude, I prefer nude better than pearl. Pearl is just white color, nude has a bit of sparkle.

I also used sephora color iq, my result was 2Y05. I knew it was wrong, my skin tone has always been cool and fair. It recommended me Bobbi Brown long wear foundation 3.5 warm beige. I put it on my left side on my face that it looked nice.  After I went home, I looked at the mirror, I was so surprised that my face on the left was so yellow. I will never buy any foundations which is recommended by the color iq test.