Ecommerce Incremental handling Charges

Thus, in admin. we have a setup page that looks like this:

By Subtotal
10     2.50
20     3.75
30     5.25
40     5.80
50     6.10
over  6.50

IMScart reads the above (customer configurable) file like a price schedule. If the order's subtotal is $10.00 or less, this calculation's charge is $2.50; if the subtotal is $20.00 or less (so, $10.01-$20.00), the charge is $3.75; and so on.

IMScart ecommerce product section uses the first line of the file to decide which value to compare to (in this case, the subtotal), then moves down line by line seeing if this value is less than or equal to the first field of the line. If a match is made, the second field on that line is the charge for the calculation.