Cash flow modeling (calculation)

Hello!

Tell me please, if there are any tools (BADI, func.modules...) in FSCM for cash flow modeling?
For example, I have Interest Rate Instrument (55A) with placement of 100 USD and monthly repayment - twice for 50 USD. If in the first month ahead of schedule I create repay 30 USD, the cash flow is automatically adjusted from: 50 / 50 to: 30 / 35 / 35 USD. So, I can calculate cash flow by hands in the FTR_EDIT transaction. But is there any tools

(BADI, func.modules...) of cash flow calculation?