Comparison date ranges are not static - they will roll over time as the calendar turns if you've selected things like "compare to prior month". For instance, when we move into June, any prior month comparisons will move to May. You can inspect the auto-created calculated metric "Percent Change" - it has date segments applied to it, and in those date segments you can see the rolling logic of the range.
However, the date comparisons will not change if the panel date range is manually changed. After initial creation, they are independent of the panel range selected and instead are based on today being today.
We will certainly consider allowing for the comparisons to be controlled by the panel calendar though. We appreciate this feedback!
I believe that when you run a percent change comparison, the percent change column is calculated based on the date that was applied to the column at the time the option was selected. This would cause the percent change value to remain static, even when applying a different time frame to the column.
As a workaround, I've created custom percent change metrics comparing this week visits to last week visits (daily average) and calculating the percent change for each metric needed. This allows the percent change to adjust according to the time frame selected.