The addition-only data storage implemented in FINALES allows traceability of the requests and responses. Additionally, the metadata stored with each dataset enables e.g. the identification of failed measurements, which the user may want to handle differently from successful measurements during data analysis. However, an agreement on the handling of missing values proved to be crucial even outside the optimizer agent. Missing values can originate from failures during data generation or upon merging data from various sources, where some quantities are by design not provided by all services. Compliance with the schemas offered by FINALES requires the necessary fields to be filled with an appropriate data type. However, it needs to be possible to filter for invalid or unavailable data. Therefore, either filling values need to be chosen, which are universally applicable for all agents, or each individual value needs to be labelled regarding its validity. Both approaches have limitations for some kinds of results. So, care must be taken when deciding for one solution or the other. A mixed approach could also be worth to be considered.