Line graph Conditional reference line

[gprejlek]

Hi,

I need som help. I would like to create a a lower limit reference line which value is depends on date. (you see on the bottom a green line changes from -0.7 to -0.8 but it is not a reference line it is a measure it this case).

I tried with the next expression but it not works.

=if([Full date])<date#('2021-02-19', 'YYYY-MM-DD'),-0.7,if([Full date]>=date#('2021-02-19', 'YYYY-MM-DD'),-0.8,2))

Could anyone help how to change the expression?