A material loading system, comprising a material loading vehicle and a material receiving vehicle configured to receive material from the material loading vehicle, the material loading system further comprising: a mobile device with a fill control application configured to run on the mobile device, the mobile device including a mobile device communication system configured to communicate with a material loading vehicle communication system on the material loading vehicle, the fill control application including: a command processing system that receives a motion adjustment command from the material loading vehicle, the motion adjustment command comprising a relative position adjustment command requesting a change in a position of the receiving vehicle relative to the material loading vehicle, the command processing system being configured to identify a requested motion adjustment to the motion of the receiving vehicle, based on the motion adjustment command; and an output generator configured to generate a representation of a visual adjustment indicator indicative of the requested motion adjustment to the motion of the receiving vehicle, the output generator configured to generate the representation of the adjustment indicator as a visual adjustment indicator that indicates a direction of the requested adjustment to the position of the receiving vehicle relative to the material loading vehicle; wherein the output generator comprises an image output generator configured to generate the visual adjustment indicator as an image of the receiving vehicle and a direction indicator indicating a direction of adjustment based on the requested adjustment to the position of the receiving vehicle relative to the material loading vehicle; an interface control signal generator configured to generate interface control signals based on the representation of the adjustment indicator; and a visual user interface mechanism coupled to the output generator and configured to generate an operator perceptible output based on the interface control signals on a display screen configured to display the visual adjustment indicator. a mobile device with a fill control application configured to run on the mobile device, the mobile device including a mobile device communication system configured to communicate with a material loading vehicle communication system on the material loading vehicle, the fill control application including: a command processing system that receives a motion adjustment command from the material loading vehicle, the motion adjustment command comprising a relative position adjustment command requesting a change in a position of the receiving vehicle relative to the material loading vehicle, the command processing system being configured to identify a requested motion adjustment to the motion of the receiving vehicle, based on the motion adjustment command; and an output generator configured to generate a representation of a visual adjustment indicator indicative of the requested motion adjustment to the motion of the receiving vehicle, the output generator configured to generate the representation of the adjustment indicator as a visual adjustment indicator that indicates a direction of the requested adjustment to the position of the receiving vehicle relative to the material loading vehicle; wherein the output generator comprises an image output generator configured to generate the visual adjustment indicator as an image of the receiving vehicle and a direction indicator indicating a direction of adjustment based on the requested adjustment to the position of the receiving vehicle relative to the material loading vehicle; an interface control signal generator configured to generate interface control signals based on the representation of the adjustment indicator; and a visual user interface mechanism coupled to the output generator and configured to generate an operator perceptible output based on the interface control signals on a display screen configured to display the visual adjustment indicator.