A work vehicle includes a work implement. A control system for the work vehicle includes a controller that controls the work implement. The controller obtains a first design topography. The controller determines a second design topography. At least a portion of the second design topography is positioned above the first design topography. The controller generates a command signal to operate the work implement in accordance with the second target design topography. The controller changes a tilt angle of the work implement when at least a portion of the second design topography is positioned below the first design topography.