Magento: Allow non-unique discount coupons, fix hire cart logic

We need a good dev to help edit PHP on the backend of our Magento site. One task should be easy, the other perhaps more difficult: Task 1: Disable the unique coupon feature in Magento, so we can create multiple different discounts, all using the same coupon code. Here is an example ([login to view URL]) Task 2: Edit custom PHP logic that adds items to our magento cart. Our site currently allows customers to hire products so that when they add items to the shopping cart, it also adds a deposit amount. The product is charged to their CC, and the the deposit amount is 'authorized' so that we can charge later if they don't return the items. Another developer set this up and it works great, except that they couldn't make it work with more than one hire item in the cart at once. We need someone to take a look at the script that has been written, and figure out a way to make this work with more than one hire item at a time. We have all the documentation.