The use of SO in "the same manner or to the same extent as aforementioned; also"
so - Wiktionary gives these quotations:
‘There’re another two.’ ‘So there are.’
Why is the first one inverted and the second one not? I read it somewhere that it is because the answer of the second quotation confirms the first sentence (aforementioned stuff), so it is not allowed to invert. First, I can’t find another source that corraborates this reasoning. Second, why is it not allowed to invert? There must be a specific reason for this subject–auxiliary inversion.