% change average for Graph with multiple weeks

kurtrod , You need to have table with Year(FY), Week, and year week and join it back with you table

Create a new week rank column

Week Rank = RANKX('Date','Date'[Year Week],,ASC,Dense) //YYYYWW format

then have measure

This Week = CALCULATE(sum('Table'[Qty]), FILTER(ALL('Date'),'Date'[Week Rank]=max('Date'[Week Rank])))
Last Week = CALCULATE(sum('Table'[Qty]), FILTER(ALL('Date'),'Date'[Week Rank]=max('Date'[Week Rank])-1))

This Week= CALCULATE(sum('Table'[Qty]), FILTER(ALL('Date'),'Date'[Year]=max('Date'[Year]) && 'Date'[Week] = Max('Date'[Week]) ))
Last Year Week = CALCULATE(sum('Table'[Qty]), FILTER(ALL('Date'),'Date'[Year]=max('Date'[Year])-1 && 'Date'[Week] = Max('Date'[Week])))

Power BI — Week on Week and WTD
https://medium.com/@amitchandak.1978/power-bi-wtd-questions-time-intelligence-4-5-98c30fab69d3
https://community.powerbi.com/t5/Community-Blog/Week-Is-Not-So-Weak-WTD-Last-WTD-and-This-Week-vs-Last-Week/ba-p/1051123
https://www.youtube.com/watch?v=pnAesWxYgJ8