If you are using an Android OS cellphone then you may noticed, the clock of your cellphone moves one hour forward.Due to daylight saving the difference from GMT+ 5 now moves to +6.
By unchecking auto time update with network not solve your problem.The time zone selection showing +6 for Karachi, Islamabad.
Due to this issue time of text messages also showing one hour forward.
This is all because Pakistan is in number of those countries which used day light saving in summer.But from past two or three years the government of pakistan announced not to carry more daylight saving for power shortage.
If you are using windows Mobile and your clock moves one hour forward, you can install patch file which is available for download from microsoft website to fix this bug and to set your time zone at+ 5 in summer.