This is really speculation. There is no reliable source to confirm this. I have used Robinhood for over 6 months now and never observed the trade price deviate

This is really speculation. There is no reliable source to confirm this. I have used Robinhood for over 6 months now and never observed the trade price deviate from what is listed on Schwab and IB. Also, for most people who trade 100-1000 shares it doesn't really matter.