Worldpay Price dependant payment module

[hrhstephen]

I can successfully enable/disable worldpay module by price so i can now seperate cheap (50p) debit card transactions, and expensive (4.5%) credit card transactions and use cheaper nochex as necessary.

worldpay.php, Disable if amount is less than £11:

$this->enabled = ((MODULE_PAYMENT_WORLDPAY_DC_STATUS == 'True')? true : false);
if ( $order->info['total' ] < 11) {
$this ->enabled = false;
}

If I set $this ->enabled = true; it works but the condition is not what I want it will not disable if less than £11.

What is more baffling is that I have another worldpay module called worldpay_cc.php

$this-> enabled = (( MODULE_PAYMENT_WORLDPAY_CC_STATUS == 'True') ? true : false);
if ( ( $order->info['total' ] < 300) && ( $order->info['total' ] > 11)) {
$this ->enabled = false;
}

This one works no problem, if I copy this if statement to the other worldpay.php that works as well.

The problem is that dependent on the if condition worldpay works or does not work, I get error in worldpay website:

Sorry, there was an error in processing this transaction:
The information sent from the merchant's site is invalid or incomplete. Please send the following information to the merchant:
The transaction cannot be processed due to one or more of the following:

the installation ID field is blank or contains invalid characters
a different submission protocol is required. For instance, a more secure submission may be required
the installation number is invalid

I have searched the forums but no-one seems to have tested this in v1.6/1.8 which has global $order;

[hrhstephen]

Thank God! Solved it after much prayer and loads of frustrating nights…

Looks like payment modules get called twice, before being sent off to card companies.

Once at checkout_payment.php, and again at checkout_confirmation.php

$order->info['total' ] is ok the first time, which is what I use for checking the order value, the second time it is null, so I simply make sure it is not null when disabling the payment module, works with worldpay and nochex….

// BOM
// Dynamic disable mod 24/05/06 Disable for trades less than £11
        if ( ($this->enabled == true) && ( $order->info['total' ] < 11) && ( $order->info['total' ] !=null) ) {
          $this->enabled = false;
      }
// EOM

Can anyone tell me if my mod will cause problems elsewhere? As I am not brilliant at php, and only worked this out by echoing variables during the checkout process.