This pattern describes how to compute week-related calculations, such as year-to-date, same period last year, and percentage growth using a week granularity. This pattern does not rely on DAX built-in time intelligence functions. All the measures refer to the fiscal calendar because the nature of a calendar based on weeks is not compatible with the definition of months in a regular Gregorian calendar.
In case your requirements cannot be fulfilled by week-related calculations using a week-based calendar, then you should use another pattern. Check the Time-related calculations introduction to figure out what is the right pattern for your scenario.