We consider the forward link of a multibeam satellite system with high spectral reuse and the novel low-complexity transmission and detection strategies from ["“Exploratory analysis of superposition coding and rate splitting for multibeam satellite systems", ISWCS 2018]. More specifically, we study the impact of a time offset between the antenna beams that cooperate to simultaneously serve a given user. Assuming Gaussian signaling, we provide closed-form expressions for the achievable rate region. It is demonstrated that, in the absence of timing information at the gateway, this region is not affected by a time offset. Our numerical results further show that, in case timing is known at the gateway, an offset of half a symbol period at both user terminals is optimal in terms of spectral efficiency.