Its more like this. If you do a tar -tvf and you see that the paths are
myfiles/file1.txt
myfiles/file2.txt
if you put the tar file in /usr and extract it then the path for the files become
/usr/myfiles/file1.txt
/usr/myfiles/file2.txt

the only exception is if you do a tar -tvf and you see the paths are
/myfiles/file1.txt
/myfiles/file2.txt
then because of that leading / the file path for the files will become
/myfiles/file1.txt
/myfiles/file2.txt
no matter where you extract the tar.

Hope that makes makes it easier