We have just released the premium version and are currently waiting for feedback from users about it. In the future, we plan to make several options for subscription.
Trips (Start/End) notifications are generated immediately when the start and end of a trip is determined, depending on both the incoming speed data and the change in location. This usually does not take long time. Could you tell us in more detail about what period of time we are talking about in your case? Notifications can be received out of time if some of the data comes from the black box with a time delay. Is it possible that your tracker collects data in a black box and then sends it in batches after a while?