Based on the answers provided, the following corrections need to be made to the 3D object:

1. Adjust the extrusion of the smaller rectangle so that it is clearly almost twice as much as the larger rectangle. This might require adjusting the extrusion of both rectangles to achieve the desired ratio.

2. Reposition the smaller rectangle so that it is centered at the same point as the larger rectangle. This will require moving the smaller rectangle towards the center of the larger one.

3. Adjust the dimensions of the smaller rectangle so that its length and width are approximately half of those of the larger rectangle. This might require resizing the smaller rectangle to achieve the desired proportions.