Auto Number Field dependent on type of invoice

Auto Number Field dependent on type of invoice

Hello again! Im often here lately.

I've created my Invoice template and as other users suggested I used autonumber field to populate Invoice number. In my country there are 2 invoice types. Ones that do not need to be numbered and are just an information document for the customer and the second type which is a document confirming his payment that lands on my accountant desk.

The problem is - they both look the same, are just named differently. Both are invoices. That means if I create a "information invoice" zoho treats it as regular invoice and increases the auto number field.

While I can remove autonumber field on the "information invoice" it does not change the fact that every time I create this type of invoice, the number of total invoices changes.

I need autonumber field to work only on Invoices confirming the payment.

Is there any way I can achieve this without typing it all by hand?

Thank you.