Have you done the tests after rebooting your MBA? For me it takes long time (>10 seconds) only direct after reboot. When I close an app and open again, then there is no high load time.
I just have after reading your post, the times are slightly different, but how much of that is down to my reaction time, or the apps, well, there's give or take as there's really not a lot in it. As far as I can tell the slow launching has been completely rectified in the 1.9.1 releases on my system.
Anyway, after a cold boot of my MacBook Air these are the times I got: 2.87 for Photo, 2.71 for Designer and 3.01 for Publisher.