if (amountToPay.compareTo(calculateTotalAmountToPay(event, when)) != 0) {
if (amountToPay.compareTo(calculateTotalAmountToPay(event, when)) < 0) {
    private void checkIfCanAddAmount(Money amountToPay, final Event event, final DateTime when) {	if (amountToPay.compareTo(calculateTotalAmountToPay(event, when)) != 0) {	    throw new DomainExceptionWithLabelFormatter(		    "error.accounting.postingRules.FixedAmountPR.amount.being.payed.must.match.amount.to.pay",		    event.getDescriptionForEntryType(getEntryType()));	}    }