Behavior support applications require an understanding of the user's values to provide personalized support. User models have been developed to capture this relationship, but they may not always address unforeseen circumstances due to the changing nature of human values. To address this, the ability to update value models in real-time is crucial. This paper presents a study on the design of a graphical user interface (GUI) that utilizes behavior trees to elicit and update personal values. The study focuses on comparing the accuracy and usability of different questioning techniques, specifically comparative questions and isolation questions, and user interfaces. The results show that GUI with isolation questions and text user interface with comparative questions performed better in terms of accuracy compared to GUI with comparative questions. The study also highlights the possible impact of discrepancies in experimental procedures on the results. Furthermore, the limitations of the behavior tree model and the need for model improvements are discussed. Future work is proposed to address these limitations and explore enhancements such as alternative models, supervised processes for baseline tree building, frictionless elicitation techniques, consideration of random value shifts and big life events, and the potential of large language models. Overall, the findings contribute to the understanding of eliciting and updating user value models in personalized systems.