The hierarchic layout algorithm uses a complex network of constraints to determine the horizontal position of nodes. Thus it strongly depends on the structure of your diagram whether or not levels are centered. Of course, there is also the possibility of an error in the algorithm that might prevent a centered arrangement.
If you upload a GraphML file of your diagram here, I will take a look and let you know if it is possible to get centered levels. (If your diagram contains sensitive data, please use "Tools" -> "Anonymize" to remove all such data before uploading.)
Here is the GraphML file of my diagram. It has been anonymized.
Thank you for looking at this. It is appreciated.