Formula for Project Stage & Start & Finish Date

americansurveymanagement35236

Based on my attached images, I am looking for a formula that will auto fill my Start Date when my Project Stage = "Scheduled" and populate Finish Date when Project Stage = "Invoiced". Any help will greatly be appreciated. Thanks.

americansurveymanagement35236

I keep circular reference error when I try the following Formula:

=IF([PROJECT STAGE]238 = "Scheduled", [START DATE]238, MONTH(@cell) = MONTH(TODAY()))