1. Now may be after a week, he'll need one more license, so i want to automate his invoicing/billing to 3 weeks (prorate), how can i do this in automated way?

2. Also, as he is my client now and while signing up for initial 5 users, he did put all the details (such as name, address, credit card details etc), so when he comes to buy one more license, i don't want to ask him all that info again, just the product sku, quantity and let him pay, is there a way to create kind of login where he logs in and see all his info instead of putting it again?

thank you