Different thickness levels not imported from Google Fonts

First of all: thanks for the module!

I noticed though that not all different versions of thickness are imported for Google Fonts. For example: "Roboto" has 100, 300, 400, 500, 700 and 900. For-your-face seems not to import the 400. I updated Google Font database under config, but it seems not to be in the list.

Any particular reason for this?