Addition of fixed and variable charges

[divyendu]

I have just installed MVS 1.1 with the oscommerce.

My vendors charges me according to the UPS but they also charges extra handling fees like $5 per order and $2 per item subject to the maximum of $10 for 5 items.

For example.

If a person orders 3 items for same vendor then shipping charges will be that of given by UPS plus $11 ($5 for order +$2*3 items)

If a person orders 7 items for same vendor then shipping charges will be that of given by UPS plus $15 ($5 for order +$2*5 for maximum items)

 

Please guide me how to include this kind of calculation.

Thanks

Divyendu