Save up ordered products/domains for invoicing
When first going to a new client it might happen that the client wants X product and minutes after that also wants Y product, so we arrange that on location (2 invoices already). It'd be nice to have the option to wait with billing till the 1st day of the next month, or for ex. till the next day, so that changes can still be done.
This way it's possible to add another product Z (third invoice), and consolidate it into 1 invoice, without having to merge them (my accountant will surely hate me then).