Amazon registry question

I'm a prime member and I'll be eligible for my 15% discount soon(for one bulk order of whatever is left on my registry). My question is can I keep adding stuff after the completion date and still include it for my 15%? Second question is can I add non-baby items and get the 15% off? Hate to take advantage but we are very loyal amazon customers so I feel like i deserve it if it'll let me?  Thanks!!