My objects Project and Plan are master objects to "All projects" which is the junction object. I also have an object called "Activity" that is a child to Project and a lookup to the All Projects Junction object. I ultimately want a time field on Activity to roll up to Plan. I have created a roll up summary field called Total Time on the Project object that rolls up the time fields from the Activity objects, I then have a cross object formula field on the Junction object that pulls from the Total Time field on the project object, lets call this A. Since a roll up summary can't run from a formula field and I couldn't do a field update from a cross object formula, I then created another formula field on the Junction object, call it B, that pulls from the cross object formula field (A) on the junction object. Then I have another field on the junction object, call it C, that I want to be updated with the value in B. Basically I want C to mirror B and it's only there so that I can then do a roll up summary field on Plan of C. C will update if I click edit save on the junction object but not when I change time on the activity object. I've tried the following criteria in the workflow rule: when the time value on the Activity object >0, field B is different than prior, when modified dates is changed, when time field on the project object is changed, etc. What criteria can I use to make it update automatically?