, hello, I added a lot of time driving job, some less than a minute apart, then came the day job today have delay, up to 68 seconds at least 5 seconds, also appeared before and after the job delay time is not the same situation, such as x homework 1:10:00 y homework is 1:10:30 began, delayed 55 seconds x y delayed 25 seconds, the last two should stagger to perform the job carried out at the same time, and also does not have an error in the sz20,