Hi,philip_clarke

I think I will try to explain why I need this surcharge, so may help you to plan writing the codes.

I have protx on my site and it is the cheapest payment gateway in the UK so far. Worldpay is expensive, but I will use worldpay as alternative and backup. Because protx is not prefect and it always happen that some customers fail to pay via protx. I would prefer my customers use protx to pay if they can. If for some reasons they are unable pay via protx, worldpay can be put into use. Every time my customers pay via worldpay, I will loss some profit. that is why I would like to have surcharge on worldpay, to deter customes from choose worldpay without trying protx first. I will put some wording something like "We prefer customers pay by 1st payment option, and only use 2nd payment option when unable to pay by 1st payment option, since the worldpay is more expensive" in area say "please choose payment method". then customes still choose worldpay and pay by credit card, we can reasonable add surcharge on it. they have been warning beforehand.

although the different charge between protx and worldpay may be very tiny per transcation, but it will add up and become a large amount in long run.

no sure anyone will agree, but this is what I though.

thank you for your help and really appreciate it.