Instructor's update applies to that of the team editions for A6. With the instructor's license, like with the team license, you can install Gamestudio on multiple computers, the limit being the number of licenses bought. With A6, you cannot publish the game, and the same project must be worked on (or for educational use only (not sure on this one)) by the entire team.

Edit: With a "normal" edition, you can only install the program on one computer and can do any number of projects, and you can also publish with a normal edition.