In the Client Data it states the assessment day is 28 days from start on site.
The assessment day should be stated as a particular day of each month. As it is stated as 28 days from start on Site, then you could use that day as the continuing assessment date for each subsequent month. For instance if 28 days from start on Site was the 15th, then you could use the 15th of each subsequent month as the assessment day for that month.
A payment assessment is made by the Contractor prior to each assessment day, so before the 15th in the above example, which is the payment application. If no payment application is submitted then the Client assesses the amount due. Payment is made within 3 weeks after the assessment day.
If the ‘Construction Act’ applies (HGCRA as amended) then the above represents a Payee led procedure, that is the application for payment becomes the payment notice and the Client would essentially give a notice to pay less than the notified sum not later than 7 days prior to the final date for payment if it intends to pay less than the Contractor’s payment application.
The timescales are also adjusted where they include certain days (Bank Holidays etc) in accordance with s116 of the ‘Construction Act’.