Entries are getting logged twice in AQ_QUEUE with different steps

We are changing some values/rates in Products or Discounts , At a time only one thing is changed. Say product Description.

However, when we see in AQ_SYNC (Table of AQ_QUEUE ) the entries are logged twice in that. Both looks identical just that they mention step_no as 0 and step_no as 1 , which is the only distinct thing.

We tried searching for its significance but not able to find.

What is the significance of the multiple login of same event in the queue. ?

Do the step_no mean anything  in queue table?

As otherwise , we would like to capture only one entry,