If its recurring journal then journal template will help but then journal posting is required. So far we are doing the similar way as you do. I know there should be some facility on the application front end where like data, one can copy the posted journal. Consolidation or calculation never take place automatically after the copied journal.
Unfortunately, there are only 3rd party tools that can actually copy the journals from one scenario to another. The usual way, is what you mentioned in your post: extract the journals, edit the file and reload it.
A solution to this issue is to write a rule that will copy only the values of the journal to the target scenario and not the journal itself. So, copy ECA to ECA and PCA to PCA.
If anyone else, have a third solution please post it in order to get a better understanding of the module.