Relative Report Level Filter in addiction to last entry

Hello togehter,

i have a new challenge for my report skills. i would set a filter for a diagram like this:

from max(sale_date) to max(sale_date)-30 days or 4 weeks or so. I want to show a review of the sale development of the last weeks. 

Ex:

last sale = 13.09.2018

then filter from 16.08.2018 to 13.09.2018. Its equal for these if its excatly 30days four weeks or one month.

Know anyone something to realize these in Power Bi?

Many thanks

Pascal