THis is my data, I need to set a reminder so I dont miss the deadlines

E5 F5
19 May 2006 15 November 2006
26 August 2005 22 February 2006
27 August 2005 23 February 2006

I plan the next date by E5+180, this works but when I try to use
conditional formating it fails.

I need to change to Green if +120 days and Red if 160 days

Sorry if I am being thick and thanks for your help