Question about Unwrap UVW and Instances

[ForgeInteractive]

Hello all.

I'm relatively new to modeling and texturing. I recently purchased a book that had a great section on modeling and texturing a model for use in games. Everything seems to have worked fine but I have some questions that aren't explained in the book. (I'm using 3Ds Max 2012)

I created an object that had some pieces that were instances. When it came time to unwrap and texture, I took 1 of the instances and unwrapped it. When it came time to texture the entire model, I attached all the pieces and did another Unwrap UVW modifier. I tried the 'pack' buttons on the Edit UVW window and I was surprised to see every instance unwrapped. Not just the 1 but all 8 instances were unwrapped. Is this normal and is this how it should work?

When I didn't use the pack operations, all of the maps were layed on top of each other which seems to work just fine for mapping.

But, again, my questions are:
Should I get all 8 maps?
Is having them layered the 'correct' way to create the UVW?

Thanks in advance.