Modeling of the value transfer of service based business systems is often based on the value normalization in terms of the value of money. We identify that the normalization is neither applicable for not normalizable properties of services of XaaS/EaaS(everything as a service) nor contributing to modeling the business nature of service based systems. We explore from a knowledge engineering approach the foundation of value modeling factors including "unit of account" and "value normalization". We propose a holistic formula for assisting tradeoffs on the modeling factors. We identify possible not normalizable situations and introduce a service value broker mode as solution initiatives with demonstrative cases.