ITER blanket modules (BMs) are arranged around the plasma to provide thermal and nuclear shielding for the vacuum vessel, magnets and other external components. Detailed mapping of nuclear heating, radiation damage, and helium production is an essential input to the design process. During initial investigation of a BM design, some simplifications of the BM may be needed. Nuclear heating was determined for four CAD based models of the BM04 region (located at the inboard mid-plane) including 1) a detailed 3-D geometry with a detailed 3-D source, 2) a detailed 3-D geometry with a uniformly distributed source, 3) a homogenized 3-D geometry with a detailed 3-D source, and, 4) a homogenized 3-D geometry with a uniformly distributed source. The results show that the impact of using homogenized models is larger than that of using a uniformly distributed source. These results are being incorporated into the BM design process by using more detail in homogenized models when detailed CAD based models are not available.