drawing time vs stopped time does not take into account the non-mechanical part of the process: the work that happens between the ears.
Personal thoughts: If I were a freelancer I would probably not want my work methods recorded, especially if it is exactly that what generates the livelihood. Additionally, recording the screen and saving it somewhere pose a rather big security risk. Also, the proposed measurements sound like they would lead to an unhealthy amoung of micromanagement.
That said: there is no screen recording feature in Rhino.