If you are buying a bunch of computers, you might consider the small business discounts for Apple. Given how much Apple gear I see companies buying.
There are two hassles. When you sign up it will barf on the phone number you supply. It needs a specific format but doesn't tell you want it is.
The form it must have is "206-XXX-XXXX" that is no international codes and dashes.
The second thing is that you have to call to find your discount for volume purchases. We were getting 2-5% a few years ago which was nice!
Small and Medium-Size Businesses - Apple
— Read on www.apple.com/retail/business/