Thanks for your reply.
I brought my two MBA's to Best Buy to do side by side comparison, there are two 2012 MBA's in demo. One is 11" and the other is 13". The result is interesting:
The 11" MBA in BB is as reflective as my new 2012 13" MBA. The 13" MBA in BB is obviously less reflective to these two MBA and is similar to my old 2011 13" MBA. I test the reflection by turing off the backlight and adjust the display angle to reflect the light bulbs above my head. The reflection of my old 2011 13" MBA and the 2012 13" MBA in BB are both dimmed with a purple color. The color of the light bulb reflection on the other two MBA's is more close to the color of the light bulb. (There is a photo of reflectiveness comparison of MBA and MBPR 13" in the photo# 2012-MBPR13-14 of
http://iphone4.tw/forums/showthread.php?t=191501. The reflectiveness of the more reflective MBA's looks more close to MBPR in this photo.)
I thought the reason of different reflectiveness might be caused by different panel manufactures. But it seems not. These are the panel serial's of these MBA's:
less reflective:
2011 13" MBA (my old machine):LTH133BT01A03
2012 13" MBA (demo in BB):LP133WP1-TJA3
more reflective:
2012 13" MBA (My new CTO machine):LP133WP1-TJA7
2012 11" MBA (demo in BB):LTH116AT01A04
I found the only 2012 MBA being less reflective in BB might be manufactured earliest among the three 2012 MBA's because the hinge of the screen of this machine is very loose.