> The SEC has stated that “routing order flow for automated execution, or internally executing order flow on an auto- mated basis, at the best bid or offer quotation, would not necessarily satisfy a broker-dealer’s duty of best execution for small orders in listed and OTC securities.” The reasoning behind this view is that prices better than the NBBO may be readily accessible to the member."
I also found more evidence your position on FINRA here (pdf):
https://www.finra.org/sites/default/files/NoticeDocument/p00...
It reads:
> The SEC has stated that “routing order flow for automated execution, or internally executing order flow on an auto- mated basis, at the best bid or offer quotation, would not necessarily satisfy a broker-dealer’s duty of best execution for small orders in listed and OTC securities.” The reasoning behind this view is that prices better than the NBBO may be readily accessible to the member."