The invoicing arrangements will be set out in the Contract on a project specific basis. Commonly, a draft invoice should be sent to the Board shortly after the end of each month or no earlier than the middle of the month to which it relates. This invoice sets out the standard payment due to the Contractor minus any agreed deductions for poor performance (see paragraph 11). It is likely to take time to calculate and agree the level of any such deductions, so these may be taken out of the following month's service payment. Therefore, February's invoice (issued shortly after the end of that month) would contain any deductions in respect of January and would be due for payment a certain number of days (say, 28) after receipt by the Board.