More and more organisations in Portugal invest in Blended Learning (BL) courses for their staff members, mainly for the flexibility and lower costs of this format. This trend also includes language courses delivered in Portuguese and multinational companies that intend to embrace the global economy. As such, the English language has become a necessary tool to be part of the globalised market. As uncertainty still persists for learners and companies regarding the learning outcomes and return on investment of Blended Learning (BL) Courses, new challenges have also emerged for teachers and researchers. From our almost 15 years of teaching experience with e-learning platforms, as students' level of proficiency increases, a decrease in time spent online can be observed. Does this correspond to lower grades? Within this scope, one may question how efficient this format may be for language learners as their level of proficiency increases. The aim of this study is to assess whether this model is appropriate for all levels of proficiency. In other words, we will try to examine the efficiency of the BL format in an EFL training course delivered in company. The study is carried out by comparing the final grades and online self-study time of students ranging from A to B levels, in accordance with the Common European Framework of Reference. We aim to identify the possible impact the decrease in online self-study time of students - observed as their level of proficiency increases - has on their results. Is there a difference in BL course effectiveness depending on students' level of proficiency? Do Intermediate to Upper-Intermediate students benefit as much from BL courses as their peers at a Beginner level? Does one size, i.e., the same BL approach, not fit all?
