cron changes not effective on following minute of the change?

[Mayuresh <mayuresh%acm.org@localhost>]

A cron job such as the following
* * * * * date

will send a mail every minute with the command's output.

I realize that the job doesn't trigger on the following minute of setting
it up. It triggers only on the subsequent following minute.

Is this by design? Any reason why it behaves so on NetBSD?

Mayuresh.