Hi ​@mmusab hope all is well.

We see your issue is mainly with circular reference, to avoid the circular reference I believe you can reverse the logic by starting from your output:

Here’s a little model to help you:

Steps:

1. Source input = the amount to start with
2. Closing balance = previous(Month) + Source input - previous(Month)*Amortisation rate
3. Amortisation = (Closing balance * amortisation rate*-1) rselect: Month-1]
4. Opening balance = Closing balancenselect: Month-1]

We do have existing models that are covering this use case and that can be added on to your workspace upon request. They are called:

• CAPEX Planning (entire application)
• CAPEX Component (component that can be added to an existing application)

If you’re under implementation, you can refer to your CSM or SA.

If you’re already implemented, you can create a support ticket to request these models.

Also, here’s an article for when building a Pigment Application is to have a formula iterate over all the Items in a Dimension, using a calculation from one Item to calculate the next.

Hope this helps answers your questions. 

Kind Regards.