Computerized dynamic assessment (C-DA) brings the rationality of assessment-instruction integration behind dynamic assessment (DA) into computerized context through the presentation of electronic mediations (Poehner). This study attempts to unravel L2 learners' actual/developed ability and learning potential in a C-DA reading comprehension context where 183 Iranian EFL learners were asked to freely select pre-specified, implicit to explicit mediations based upon their visual, audio, and textual learning preferences as well as their zone of proximal level of development. More precisely, this study seeks to discover the feasibility of integration of learners' mediating preferences into C-DA procedure. In contrast to previous C-DA studies, learners in this study played an active role in deciding on different types of visual, audio, and textual mediations required to deal with comprehending the main ideas of 15 passages. The software was programmed to present 15 reading comprehension passages alongside three sets of visual/audio/textual mediations presented strategically (implicit to explicit) in a prefabricated standardized fashion to assess and co-construct emerging zone of proximal development (ZPD). The learners' learning potential score based on their own mediation tendencies uncovered the effectiveness of visual, audio, and textual mediations in assisting the learners to reach independency in grasping the main ideas of reading comprehension passages. Statistically, a paired samples t-test revealed the learners' ZPD enhancement in comparison with their developed ability. Overall, the results demonstrated that it is feasible to respond to individual learning preferences with fine-tuned electronic mediations in the C-DA context of reading comprehension.