I am prototyping/evaluating creator.

I would like to know if there is any way to "disable" a formula field and prevent it from executing while in edit mode? 

I have a formula field that auto calculates a unique quotation ID (I sure wish there was a random number generator) based on date/time when the form is originally submitted.

I don't want this field to auto-calculate to a new unique number, every time I edit it.

Thank you in advance.