yes it should be like thatThe on field referee has the final decision. So if the on field referee sees it and says no, there has to be a threshold reached where the VAR ref says you have missed something in order to send him to the touchline and review the video footage. If the VAR ref just disagrees with the on field referees decision, that does not automatically mean that the on field referee gets to review it again. Maybe it should be like that, but VAR is not used like that at the moment. This is why every time the on field referee goes to the touchline, he overturns the original decision.
Some penalties that have been given this season have been soft and, maybe with another look at VAR, the referee would change his mind but it is only there for the clear and obvious errors, not the ones where it could go either way.
'clear and obvious' is too subjective a premise to work from, and vague enough to hide behind
Any doubt, ref should be sent to the monitor...only way to work it