Well, one concrete case is where we want to check if the hourly average response time is above a certain threshold. I know we can use the occurences to "simulate" this but it is not exactly what we want.
I am not sure whether I understood your requirement correctly but if you are looking to get the %age response time above then we can use the Compound Metric Builder'.
Once you configured correctly then we can raise the alert after 12 intervals which is equal to 1 hour.
Below screenshot is an example.