Hi @Anonymous
Pack and Go is just gathering up related files and copying them to a new location, and then updating the internal links within so that they are no longer linked to the original files, this allows you to makes changes to the new files without them updating the originals, however its not the best practice to have design files of the same name that differ, and using pack and go in this way is likely to create a giant mess very quickly.
A better approach would be to stop and adopt a proper naming scheme and folder structure.
As an example, we'll imagine that your design reuses most of the components and there are really only a handful that change from design to design... this example might or might not be the case for you, but it will demonstrate the best practices for you to consider.
So let's say re reorganize your setup as such:

These are the "custom" files named and filed in a folder reflecting their "project" with a prefix of CA50

These are the "library" files that are reused among common designs (again this is just for example, and might not reflect your real world scenario)

You could then open the assembly file and click the Copy button and select the top level assembly from the browser, this will bring in all of the files into the copy tree, where you can use the "dots" to control what is included, reused, etc.
Here the yellow dots are the reused items, blue are the ones to be copied, gray would be omitted

here the file names and folders are set, note that we need to select the "Open In New Window" button to copy the top level assembly

This will create the copies of the top level and the components to be copied in the new folder as you specified. Note they will only be in memory until you click Save for the first time and then they will get saved to the new design folder (CA-51 in this example)
So now you would just manually copy over the drawing file in Windows Explorer from the CA-50 folder to the CA-51 folder and rename it from CA50.dwg to CA51.dwg
Then just open the CA51.dwg file and use the "Replace Model Reference" button to update the drawing links from the 50 to the 51 assembly

Now you're set up to make design copies in an organized manner without creating a lot of duplicate files and no mess.
This might take a bit more forethought and planning on the front end and seem like more steps than the pack and go method, but having an organized and well thought out folder and file naming scheme will pay off in a huge way in a very short time... versus using the pack and go method to create different files of the same name, which turns into a mess very quickly.
Note too that there are other methods for copying designs in Inventor to be aware of as well:
https://cadsetterout.com/inventor-tutorials/copy-an-autodesk-inventor-design/
I hope this helps.
Best of luck to you in all of your Inventor pursuits,
Curtis
http://inventortrenches.blogspot.com