Nero 6.6 and LAME settings

I am using Nero and have successfully installed the LAME nxlame.dll. I don’t understand the settings though: The very first setting is Encoder and ranges from 0 to 9, with zero being “low” and 9 being “high”.
What does this stand for? Time, compression, quality? I tried two runs with Alt-Preset “very fast”, one at 0, the other at 9 and the time and size of the result was identical.

Thanks for help!