Till now i was under a impression that when we call an external action only it's local data table is imported. But today i saw that QTP sometimes import Global DataTable also for some actions and for some it does not.
These actions where created in QTP8.2. I created a new action tries to reproduce the same behavior in QTP9.2 but failed. But on the system with QTP8.2 it's importing the global data table data also.
Another update on the issue. I was able to replicate the issue. When you create a Re-Usable action using Insert Call to new... then only local data table is imported and in case you make the default Action1 of the test as re-usable then both local and global data table are added to the test.