Tax Simulator is not calculating tax

We've recently installed the Tax Simulator Functionality in our R12 environment, to do some checks on existing and new eBTax setup.

However the Tax Simulator is not giving any tax calculations, which is strange since creating an AP invoice in AP module is creating tax calculations.

Is there any specific setup to be done for the tax simulator, next to the standard regime-to-rate setup?

Following note already review, but no answers found: Doc ID 1906992.1