If you don't mind using continuous ranges (of Weeks) to compare --
as one could see in your TEST workbook (comparing Weeks 1-5 to 6-12) --
then you can apply a couple of Continuous (Green) Range Filters,
while leaving the Include Null Values flag selected (or All Values by default).
The technique is best described by Jonathan Drummey in his blog:
Please find the attached.
TEST_v10.2_YF.twbx 55.0 KB
Thank you, I had moved on from this however I believe this will do the trick as I read the blog you mentioned and have got my data working.