Based on the answers provided, here are the corrections needed for the 3D object:

1. The smaller cylinder needs to be extruded outwards from the larger cylinder, instead of being a separate entity placed on top. This will ensure that the smaller cylinder is a part of the larger one, maintaining the tiered structure but with an extrusion effect.

2. Ensure that the radius of the smaller cylinder is half the radius of the larger cylinder. This will help maintain the proportionality between the two cylinders.

3. The extrusion amount of the smaller cylinder should be less than that of the larger cylinder. This will help maintain the tiered structure and the proportionality between the two cylinders.