Error Message in Calculation: A function 'MAX' has been used in a True/False expression that is used

I really, really appreciate the time you are taking to assist me! 

Now I get a different error message once I modify your calculation. I have included a link to the practice database I am working with. All of this is based on a custom fiscal calendar year that begins, for example 01/28/16 - 01/26/17 (FY 2017).

This is why I am struggling to use the DAX Date/Time and Time Intelligence functions.

Sample data set:

https://1drv.ms/u/s!AoY5sA-v6cUciEOYS-NvMrcINYu1

New calculation error:

Here is the calculation I used:

WeekPeriod = 
Var w0 = MAX(Sales[Week])
RETURN
UNION (   
   ADDCOLUMNS( SUMMARIZE( CALCULATETABLE('Sales' , FILTER('Sales',Sales[Week] = w0) ), Sales[Week]),"Period","Last Week")  ,
   ADDCOLUMNS( SUMMARIZE( CALCULATETABLE('Sales' , FILTER('Sales',Sales[Week] >= w0 - 1) ), 'Sales'[Week]),"Period","Last 2 Weeks") ,
   ADDCOLUMNS( SUMMARIZE( CALCULATETABLE('Sales' , FILTER('Sales',Sales[Week] >= w0 -3) ), 'Sales'[Week]),"Period","Last 4 Weeks") ,
   ADDCOLUMNS( SUMMARIZE( CALCULATETABLE('Sales' , FILTER('Sales',Sales[Week] >= w0 - 11) ), 'Sales'[Week]),"Period","Last 12 Weeks") ,
   ADDCOLUMNS( SUMMARIZE( CALCULATETABLE('Sales'), Sales[Week]),"Period","Overall")
)