Hehe,
I understand that, I had to apply this to one of my oldest clients (11 Months), he always taked 8 days to pay his due Invoices, and I don't bill them in Advance, for example if you order today, next month today I will bill you. Well, I got tired after the 6th time this guy did it and applied this almost a month ago, I just have to wait and see what happends tomorrow since he's due again 😀