Permitted source format

In the `Scalable Font Production` section, it states that the font source format:
> The design source files (plus scripts) are available in your preferred font editor format.
The file formats most used are UFO, .glyphs, fontforge or fontlab 7. Fontlab V files must be converted to another format because the software runs only on older OS versions.

However, in the `Building Fonts` section, it only describes how to generate from UFO and Glyphs sources.

Given that "Fonts should be built in one step", it seems to me that fontforge / fontlab 7 sources should not be allowed in the Scalable Font Production section since they cannot be used to build in one step via fonttools (at least, as far as I know).