Time getting reduced by 1 hour

UNIX AIX
1

I am setting TZ=EST5EDT,M3.2.0/02:00:00,M11.1.0/02:00:00

Then Setting the date to Mar 14 01:40 EST

date 0314014010
Sun Mar 14 01:40:36 EDT 2010

Note that it show it EST. According to my TZ variable 01:40 Should be in EST only.
On executing date command once again it shows
date
Sun Mar 14 00:42:09 EST 2010

Note that EDT changed to EST and 01:40 reduced to 00:42

Can you help why it is happening..
I am using AIX6.1

Thanks in Advanceee

2

Are you 100% sure this has nothing to do with the setting of the clock on the motherboard?

3

May be you are in day saving mode.. DST mode ..

go to region and time settings through smitty and check it out.

4

Or check with zdump.

5

After a TZ change you MUST reboot for the changes to fully take effect.
Reboot and then test again please.
Let us know the results....