They don't mention this anywhere, but for light based communication with more distant targets where the laser would need multiple seconds to reach its target, w

They don't mention this anywhere, but for light based communication with more distant targets where the laser would need multiple seconds to reach its target, would they need to "lead the target" with the lasers pointing in both directions? Also, what about the complications due to interspersed massive bodies creating gravitational lensing?! I guess this can all be accounted for in the aiming software... but it's not very simple!