Cart Issue

[vlad1975]

We have set up the shipping as follows, with the product weight as 3.5kg:

0kg-5kg - 10.50
5.1kg-14kg - 12.50
14.1kg-20kg - 16.00
20.1kg-25kg - 19.00

and so on with the last weight being

641kg-9999kg - £450.00

When using the site, and adding the product to cart and then increasing the number of items, the shipping adds up as so:

1 item - 10.50 shipping - correct
2 items - 12.50 - correct
3 items - £12.50 - correct

but when it comes to 4 items we get £450.00, the last shipping cost in the table for items over 641kg

When adding 5 items, shipping is correct again at £16.00

If I remove the last shipping cost from the table, the cost for4 items still utilises the new last shipping cost from the table, in this case 401kg-640kg at £190.00

I tried changing the cost of the shipping on 641kg-9999kg to £16.00 and the costs worked for 4 items!!!

I can't see if we've done anything wrong, so is this a bug in the software or what, if so how can it be rectified?