Then the value of SHGCD is continuously decreasing when the solar profile angle is further increased.
The explanation of the increasing of the SHGCD for the case of 45 slat angle is that when the solar profile angle is increased from 0 to 45, more solar radiation bean can penetrate through the blind into the room.
Once the solar profile angle is greater than 45 the slat starts to block the solar radiation beam from entering into the room causing the value of SHGCD to decrease.