last-week, last-month vs. last 7 days, last 30 days

[helix123]

As it seems the values last-week, last-month of the when argument are really meant to mean last 7 days and last 30 days, respectively. Given the current names, one could suspect to get the last full week (Mon - Sun) and the last full month (1 to 28, 29, 30, or 31 days).

Thus, my suggestion is to introduce more explicit names (last-7-days, last-30-days), maybe additionally (and discourage use of last-week, last-month but allow for them as back-compatiblilty).