Sonification using audio parameter mapping involves both aesthetic and technical challenges and requires interdisciplinary skills on a high level to produce a successful result. With the aim to lower the barrier for students to enter the field of sonification, we developed and presented WebAudioXML at SMC2020. Since then, more than 40 student projects has successfully proven that the technology is highly beneficial for non-programmers to learn how to create interactive web audio applications. With this study, we present new feature for WebAudioXML that also makes advanced audio parameter mapping, data interpolation and value conversion more accessible and easy to assess. Three student projects act as base for the syntax definition and by using an annotated portfolio and video recorded interviews with experts from the sound and music computing community, we present important insights from the project. The participants contributed with critical feedback and questions that helped us to better understand the strengths and weaknesses with the proposed syntax. We conclude that the technology is robust and useful and present new ideas that emerged from this study.