FYI. Some progress, but still falling short of completion.
I have the individual shipping rates for each item being added successfully from the recordset into the shopping cart at full shipping amount for 1st, 2nd, 3rd, of each item.
Now I just need to discount the 2nd, 3rd, etc., shipping amount by 50% for each after the first item's full amount for the first.
So far this is where I am at.
Created a new eCart Column called Shipping (binding it in the "eCart add from recordset", to the table column for the shipping amount).
Calculation tab. New Calculation called "FlatRate" [Quantity] * [Shipping].
SubTotal of Quantity > 0
AND Subtotal for any column
If the subtotal of column Quantity is > a value of 0
Based on column subtotal
Subtotal of column FlatRate plus 0