ARCS - Reconciliation Balance

Summary:

Few years ago, during a demo, we saw that we can created reconciliations as below :

Meaning having a source system balance and a reconciliation balance (which is editable).

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We're now busy configuring ARCS but we can't replicate that set-up (with the reconciliation balance).

Any idea how we can achieve this?

Version (include the version you are using, if applicable):

Code Snippet (add any code snippets that support your topic, if applicable):