Activity Sequence getting Changed after Adding Duration in P6

Hello Everyone!!

Thanks to everyone for helping by having discussion on various topics.

I believe that this is the best site for the beginners and experts to learn many new things.

In one of my project plan, after entering all the activities, I started applying duration to activities. While adding duration I observe that, when ever an activity is having 1d duration it's sequence is not changing and whenever I am adding a duration of more than 1d, activity sequence is getting automatically changed.

For Instance Activity ID sequence is 001, 002, 003. and If i gave duration as 5d, 1d, 2d respectively.

My Activity ID Sequence is becoming 002, 003, 001.

I kindly request you guys to help me out in this matter. As I am beginner I am unable to get any solution for this....

Thanks to everyone in advance......:)