Well, I think I'm talking about a different thing.
I was talking about engines, not virus database or extra scannings done on-access. I understand perfectly what Polonus is trying to say.
So, Virus Total uses the same engines but, extra options that come on-access won't be present in the on-demand scanning of these check-webpages. There is heuristics somehow, but not completely.
But, Polonus, does fortiguardcenter scanning add this extra level of scanning for their particular scanner I think, nothing for the others. Am I wrong?