I imported an MMD (.pmx) model with CATS and the scale is huge. She's almost 20 meters high.

I know that the model being too big when imported is a normal issue, and that you can adjust the scale when importing, but is there system to this?
As in, are .pmx models just always oversized by a factor of x5, or x10? Or do they differ in the size disparity?
Why does this even happen?

Is it a safe bet to just always import with a scale of 0.1?