FileWriteN file without extension

Does FileWriteN function properly holds files without extension? Or maybe I'm missing something else?

Now I am trying to get working language handling with no success yet.

The contains of launcher.ini is:
[Launch]
AppName=INSTEAD
ProgramExecutable=INSTEAD\sdl-instead.exe
[Language]
Base=%PortableApps.comLocaleCode2%
CheckIfExists=%PAL:FullAppDir%\lang\%PAL:LanguageCustom%.ini
DefaultIfNotExists=en
[LanguageFile]
Type=ConfigRead
File=%PAL:FullAppDir%\appdata\insteadrc
Entry='lang = '
[FileWrite1]
Type=ConfigWrite
File=%PAL:FullAppDir%\appdata\insteadrc
Entry='lang = '
Value=%PAL:LanguageCustom%

The insteadrc contents:
lang = en