$form->{"tax_charge_$i"} = $form->{"tax_reverse_$i"} * -1;
$form->{"tax_reverse_$i"} = $form->format_amount(\%myconfig, $form->{"tax_reverse_$i"}, 2);
$form->{"tax_charge_$i"} = $form->format_amount(\%myconfig, $form->{"tax_charge_$i"}, 2);
$form->{"tax_charge_$i"} = $form->{"tax_reverse_$i"} * -1;
$form->{"tax_reverse_$i"} = $form->format_amount(\%myconfig, $form->{"tax_reverse_$i"}, 2);
$form->{"tax_charge_$i"} = $form->format_amount(\%myconfig, $form->{"tax_charge_$i"}, 2);