Confusion about the usage original separable conv and inverted bottleneck

[DanielMao2015]

Hi, after reading the source code of cpm, I found that you use inverted bottleneck(which is mobilenet v2) and separable conv(which corresponding the original mobilenet v1) in the part of "Convolutional_Pose_Machine" scope. Why didn't you use only inverted bottleneck structure instead of original separable conv?