While human-centered system design has actively sought to reduce cognitive biases in decision-making, a gap exists on the distinct role of media features in decision-support systems (DSS). Intuitively, we may presume that DSS interactivity and revisability remedy such biases. Yet, experiments reported herein reveal that combining the two features may conversely aggravate such bias. These features have been studied as distinct factors moderating bias in decision-criteria rating tasks in two experiments (sample sizes: n(1) =96 for first; for second with criteria vividness controlled, n(2)=429). Such study emanates from a novel view of DSS as persuasive communication media. Thus, a unique adaptation of Media Synchronicity Theory to a computer-human communication context ensues. This promotes the isolated study of interactivity and revisability, alongside their interaction. Hence, the study finds statistically significant bias reductions for revisability treatments without interactive feedback. Such real-time automatic feedback, surprisingly, makes no impact in the majority of cases. Vividness controlled, it is still revisability-only cases indicating any reduction in possible order effects bias (despite extra effort required). Thus, a fresh case is made to evaluate interactivity and revisability separately in DSS media, with empirical evidence that - together - they could be 'doing more harm than good'.