I have different custom invoices - one for AUS one for US. How can I have different payment information in the two templates. If I change one it changes the other.

It's great to hear that you've set up two different custom invoice templates for Australia and the US, Amanda.
 
To begin with, you are correct that if you update the payment information in one invoice template, it will also affect the others That's because invoice templates only control the design and layout, and they don't include payment information. Therefore, any updates made to payment information will automatically reflect on all templates.
 
To have different payment information for AUS and US invoices, you can manually update the payment information for each transaction when using the respective template. This ensures the correct information appears without affecting other templates.
 
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