Your heartbeat and breaths/week are also quite consistent. The issue here is that you have to have a reasonable theory of why variance in the metrics you're tracking will destroy value. And that means actual value, not whinging that standup goes too long. I like a short standup as much as anyone, but if that is a material driver of value destruction then your organisation is not ready for statistical quality control. Plus it probably goes over time consistently.

And once you start looking at the value, the lesson of software is that high variance activity is often the value add. It is the week(s) where someone implements pivot tables in Excel that creates probably billions of dollars in value over all of humanity. If that turns up as a statistical anomaly in the metrics because their line manager didn't bug them to fix bugs that week, that is a problem with the metrics not the programmer.

This isn't a Toyota production line (if you're interested in the history of this, that is no random example) where value is uniformly created with each car and optimising the daily process down to degree n creates value. This is software. The value isn't created in the same way and these tools are not powerful in driving value add decisions. Variance is untidy but by no means an enemy. It must be managed case by case in context.