in the NeroAACCodec.zip you obtained neroAacEnc.exe from, there is a PDF tutorial with info on the command line options.
your -V64 is AAC LC, TVBR 64 (using qaac.exe)
Nero only supports VBR not TVBR
-q 0.25 is (averaged) VBR 66k/b
to force 'no optimization' you would also need to use the -lc switch
eg. -q 0.25 -lc -if - -of [outputfile]
otherwise leave the -lc out and Nero will auto determine the ideal AAC profile