I have previously invoiced a client for a small portion (25%) of a total agreed fee for some consultancy work. I'm now about to send them an invoice for the next portion. Unfortunately there isn't an agreed payment schedule, but I'd like to send a record of the invoices sent and payments made (or not) to date. Is it normal to add a schedule of previous invoices and payments received to an invoice? Does this need to be kept as a separate document? Thanks!