Are you using Teamcenter to manage your data? It looks like your callout column is referencing the $CALLOUT attribute. Change the callout column's attribute to "$~C" to have the callouts change from increments of 10 to increments of 1.
The Item # on parts is the callout attribute in the NX component, also if you send your BVR to the structure manager in teamcenter, there is a sequence column. This is the same as the Callout in NX. Now if the callout in the NX attributes is overwritten there, then the callout will have a red lablel next to it. IF the callout matches the structure manager in teamcenter then you will label will be Magenta in color. See the attachments.
I'm not sure what happens when TC gets involved, but for native NX, the callout increment is controlled in the parts list settings.
This option is not in teamcenter as far as I can tell, this would be nice. But I could be missing this teamcenter setting, there are only a couple of teamcenter setting here and there.
About 3-4 years ago, I had some threads on here regarding getting the NX no, and the TC no. in sync, and after looking into it, we decided that it was easier to leave as it is OOTB.
Allright, that solves that problem, even though I do use teamcentre. How about the duplicate numbers, I.E. different parts having the same balloon number?
In native NX, you need to pick the right key field. The parts list levels option may also play a part.
No doubt, TC will add one or two more levels of its own complexity - this looks like a good place to start:
Assuming you've changed the callout to "$~C" in the Parts Lists, you should no longer see the duplicate Find No's in the Parts List. The ID's in the balloons are driven by the callouts in the Parts List, so updating the Parts List should cause the balloons to update to their new callout and you should no longer see the duplicate balloon ID's.
If you're concerned about the duplicate Find No's when viewing the assembly Structure Manager, you can manually edit the values in the Find No column. I don't believe NX would have created these duplicate Find No's under normal circumstances. It's possible that this occurred if the assembly was imported into Teamcenter, or that a user has edited the Find No's in Structure Manager.