The coupon takes 50% off from the online price. Remember, when you place the order at the customer service desk, you are ordering at $89.59. When you go to the cashier to pay for it, the 50% off coupons works on your subtotal, not the list price.
I am actually looking at my receipt from the last 50% off coupon and it shows $44.80 subtotal
So the CSR desk is the desk in the video section where you order but the cashier is in the front of the store?
If so, than that makes sense.