i am developer of the Bench'emAll!.
Bench'emAll! is not 'optimized'!
The one of the main ideas of this tool is to get the same performance as you launched each benchmark without benchemall - is to be absolutely 'transparent'.
But not every benchmark suits this idea.
Lets take SeriousSam: to make any localized version work i had to compile modified game kernel with my own code, so there is slight difference in results on some PC configurations. But its not 'optimisations', you can be sure in it.
by the way, new beta version of Bench'emAll! is ready, take it here:
any feedback about Bench'emAll! is welcome