Would you pls tell me why the value of “lockAtLeastFor” is 14m

[engineerping]

Dear team,
Thanks a lot for your distribution,

There is an example in the README.md file

_Let's say you have a task which you execute every 15 minutes and which usually takes few minutes to run. Moreover, you want to execute it at most once per 15 minutes. In that case, you can configure it like this:

import net.javacrumbs.shedlock.core.SchedulerLock;

@scheduled(cron = "0 */15 * * * *")
@SchedulerLock(name = "scheduledTaskName", lockAtMostFor = "14m", lockAtLeastFor = "14m")
public void scheduledTask() {
// do something
}_

I am a bit confused that:

1. why does the value of lockAtLeastFor is 14m instead of 1m or 2m？ After all，according to doc，Its main purpose is to prevent execution from multiple nodes in case of really short tasks and clock difference between the nodes
2. does the value of lockAtMostFor must less than 15m in the example? because of the @scheduled(cron = "0 */15 * * * *")