There are a number of business analysis calculations, such as forecasting, that often require an analysis of a sliding scale of the data from previous (complete) date periods. For example, it is fairly common that the last 3 complete months' worth of data is used to forecast the current month. In other words, if today's date is April 6, 2020, then the dates desired would be from January 1, 2020 to March 31, 2020. These sliding scales must be able to cross year boundaries as well as ensure that the date ranges calculated are exact. Being off by even a single day can sometimes greatly affect forecasts.
While Power BI has a DAX rolling average quick measure, this measure only works with days, months, quarters, and years. The reason is that DAX's time intelligence generally does not support weeks, and for good reason. Dealing with weeks tends...