The whole essence of track and trace is to get ahead of the virus.
In the first instance when person A catches it you are behind the virus. The speed at which you test and obtain a result for person A, trace and contact person B,C,D,E.....for example, and test and obtain a result for B,C,D,E....all vital to get from backward looking to ahead of the game.
I dont think it would be that difficult to analyse each of those elements and model it out as to predict that if certain timeframes arent being met we are quite simply 'wasting our time'