Implicit feedback is collecting information about software usage to understand how and when the software is used. This research tackles implicit feedback in Software Product Lines (SPLs). The need for platform-centric feedback makes SPL feedback depart from one-off-application feedback in both the artefact to be tracked (the platform vs the variant) as well as the tracking approach (indirect coding vs direct coding). Traditionally, product feedback is achieved by embedding `usage trackers' into the software's code. Yet, products are now members of the SPL portfolio, and hence, this approach conflicts with one of the main SPL tenants: reducing, if not eliminating, coding directly into the variant's code. Thus, we advocate for Product Derivation to be subject to a second transformation that precedes the construction of the variant based on the configuration model. This approach is tested through FEACKER, an extension to pure::variants. We resorted to a TAM evaluation on pure-systems GmbH employees(n=8). Observed divergences were next tackled through a focus group (n=3). The results reveal agreement in the interest in conducting feedback analysis at the platform level (perceived usefulness) while regarding FEACKER as a seamless