As someone pointed out, money up front is common in this business, I even ask for half up front. I think this could be a great point to bring out to your client that you waived the standard up front fee as a courtesy.
Another thing that I changed on my invoices is not putting term 30. I put ‘due upon receipt’ with the idea that most will pay within 30 days. I just simply feel like that puts the idea in their head that they have 4 weeks to pay when due upon receipt makes it feel like it is overdue.
The problem I see with this client is another common one ‘I will pay you when I get paid’. I am dealing with one of those right now and it will probably be the end of that relationship, basically to me that is a partnership and I doubt a check will have my name on it when the business is raking it in.