Exchange Rates Handler

Hi everyone, I recently have had to deal with exchange rates, and a thing I found really boring is to manage all the cases below:
if i start from LCY amount and i put it on FCY amount then exchrateLCYtoFCY
if i start from FCY amount and i put it on LCY amount then exchrateFCYtoLCY
and so on....
the function i post here, receive the six parameters, and depending on the values of CDFromCurrency and CDToCurrency decides what is the function to run (and if it must be run). At the end, it rounds the value to the correct amount.

Parameters:
Var Name DataType Subtype Length
No vDECAmount Decimal
No vCDFromCurrency Code 10
No vCDToCurrency Code 10
No vGMADate Date
No vDECCurrFactor Decimal
No vTFUnitAmount Boolean

Locals:
Name DataType Subtype Length
lTBCurrency Record Currency

IF vDECAmount <> 0 THEN BEGIN
  IF vCDFromCurrency <> vCDToCurrency THEN BEGIN
    IF vCDToCurrency = '' THEN BEGIN
      IF (vDECCurrFactor =  0) OR (vDECCurrFactor =  1) THEN     //Correction For Currency factor
        vDECCurrFactor := TBCurrExhRate.ExchangeRate(vGMADate,vCDFromCurrency);
      vDECAmount := TBCurrExhRate.ExchangeAmtFCYToLCY(vGMADate,vCDFromCurrency,vDECAmount,vDECCurrFactor);
    END ELSE BEGIN
      IF vCDFromCurrency = '' THEN BEGIN
        IF (vDECCurrFactor =  0) OR (vDECCurrFactor =  1) THEN  //Correction For Currency factor
          vDECCurrFactor := TBCurrExhRate.ExchangeRate(vGMADate,vCDToCurrency);
        vDECAmount := TBCurrExhRate.ExchangeAmtLCYToFCY(vGMADate,vCDToCurrency,vDECAmount,vDECCurrFactor);
      END ELSE BEGIN
        vDECAmount := TBCurrExhRate.ExchangeAmtFCYToFCY(vGMADate,vCDFromCurrency,vCDToCurrency,vDECAmount);
      END;
    END;
  END;

  IF vTFUnitAmount THEN BEGIN
    IF vCDToCurrency = '' THEN BEGIN
      TBGLSetup.GET;
      vDECAmount := ROUND(vDECAmount,TBGLSetup."Unit-Amount Rounding Precision");
    END ELSE BEGIN
      lTBCurrency.GET(vCDToCurrency);
      vDECAmount := ROUND(vDECAmount,lTBCurrency."Unit-Amount Rounding Precision");
    END;
  END ELSE BEGIN
    IF vCDToCurrency = '' THEN BEGIN
      TBGLSetup.GET;
      vDECAmount := ROUND(vDECAmount,TBGLSetup."Amount Rounding Precision");
    END ELSE BEGIN
      lTBCurrency.GET(vCDToCurrency);
      vDECAmount := ROUND(vDECAmount,lTBCurrency."Amount Rounding Precision");
    END;
  END;
END;
EXIT(vDECAmount);