Scenario: We are the subcontractor in California - our customer requires us to invoice no more than once per month. The invoice must be dated for the last weekday of the month projecting everything we think we will accomplish in that month. The customer must receive the invoice on or before the 15th of the same month. Conditional on Progress releases from our vendors must also be dated for the last day of the month, but they would only be able to include invoices up to the 10th or so when we call for the release to prepare the invoice package for our customer. I have a vendor that will not provide releases with an end of the month date because it would not include materials purchased from the date we called in for it to the actual end of the month. I can't find rules on the through dates of releases. Is this procedure of requesting "postdated to end of month" releases an industry standard or something unusual - and is it legal?