Hi Ray, this is helping a lot to get my head around the calculations..

(1) So would you think I should save the volume calculation in the product record...or I could do the calculation at checkout and save it as a variable?
(2) So I would also think when creating a product, that the client would assign it small, medium or large and have that saved in the product record.
(3) One thing I am wondering with this logic, if a customer orders one large and one small, the website would calculate it to the use the PalletWay company, as they will send large orders since they use pallets. However lets say that the client would separate that order into 2 deliveries, since the customer would receive the small item sooner as its a quick walk to the post office...but then that would mean the client would lost out money on delivery costs as the customer would have paid for 1 delivery method, but the client would send out as 2 deliveries...I guess that's up to them though,
(4) The client has provided me with the 2 different delivery companies price list, they are so indepth because each delivery company has different pricing tiers (I figured to use the 'middle tier, as there are only a few pounds in it either way. I guess its all about taking the average cost. Since its the best guess.
(5) One delivery company even has a price structure for 'zones' these zones are made up of the first 2 letters of the postcode, as it gives the location in the country, so will determine traveling distance...but I think it would be best to not use 'zones' since this would increase the calculation formula.
(6) I think maybe is to take all 3 delivery companies price list and try and determine similarities in pricing and take the average of those,
(7) So the product will store the weight and size.
(8) the shipping cost table will contain many records that will determine the cost by "weight up to" and "size (HxWxD) up to" plus delivery method (standard deliver) and the . This would then be cross checked with the related weight and size "total" of the shopping basket and then the cost is selected (the website doesn't need to know what the delivery costs relate to which delivery company....as its up to the human interaction to determine which delivery company best suits the scenario right?

Chris