On http://desktophelp.sage.co.uk/sage200/professional/Content/SOP/How%20VAT%20is%20calculated%20on%20sales%20orders.htm, it details how an order's VAT is calculated by multiplying the order net total by the VAT percentage (as opposed to doing this on a lineitem basis and then summing). However, how is the VAT calculated when an order contains items of different tax amounts?