Within the leases of fixed assets, how can I change the amount if it varies each month?

Summary:

After a new implementation within the fixed assets module in financial leases: I would like to know how the payment program changed specifically in the amount, since the company makes different payments each month, these vary according to inflation, so it is not known exactly how much to pay each month. And in addition to the amount, the change impacts the complete amortization schedule of the same asset that is being leased.

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