parameter selected column value to compare with other column to generate new column for legend usage

[Anonymous]

Hello all, i am new with power bi. I read a lot that unfortunetley we cant use parameter in new column creating but maybe someone has an idea to solve my issue.

I have a paramter as :

and done by it slicer:

and then i have table where first column is date with values of column selected by parameter
(if user select daily then daily column valies are shown, if montly then montyly column values are shown)
what i need is to take for each issue key column value calculate diffrence in dasys between created column value date and date from parameter selected column

As you can see on above to screenshots days diffrence for same issukey will be 15 when monthly is choosen and 1 if weekly is choosen. 

I think i need to have it as a column (this days diffrence between those dates) because i need it to use it as legend colour on chart
(for each parameter selected column i have bars with number of issuekeys ) and i need to put colours based if datediff < 8 or datediff<30 or datediff< 60 or datediff>60
something like this:

Any ideas how to solve it?