Sorry, but the manual is really outdated - since a long time. See e.g. changelog of Lame 3.90 from December 21 2001(!):
" --vbr-new code disabled (outdated and lower quality) and replaced with --vbr-mtrh (Both --vbr-new and --vbr-mtrh now default to mtrh)" So this manual must have been written about 4 years ago, before even the --presets existed.
I'd bet that default now defaults to vbr-old.