Distributions of V_∥ in the two simulations (High_B top, Low_B bottom) at an offset of 0.1 pc from the filaments crest when SFE = 3%. The set has been divided between filament sections closer (filled histogram) and farther (hollow histogram) than 2 pc from the cloud centre. The black dot-dashed lines give a reference sound speed for a molecular medium at 10 K. All four distributions display a shift towards negative velocities (faster flows along the filaments relative to the surrounding gas). However, the shift in peak velocity between the inner and outer distributions, evident in Low_B but absent in High_B, suggests that in a well-developed HFS the faster flow in the filaments is driven by the central potential well. This supports the conveyor belt scenario, where filaments efficiently channel material toward the hub.