But you read the stackoverflow answer?
You can do stuff like 5-59/20 which would be 5, 25, 45. If you use different starting values for each instance you'll get different times within the hour
(That way you can even be sure that at no time they overlap whereas with some weird intervals like 43 over the whole day two events could occur at the same time if they reach a common multiple )
Nope, not for the short term. It's the way the engine tells the clients about the server settings.