I clearly have forgotten how to do this. I have just increased one of my staff members salaries (in a table called people) - the wages calcs are in a related table called Wages - FM has changed all of the records in wages when I only want it from from the salary increase onward. The field in Wages is the salary field from the people table; I have tested doing as a calculation but it is updating all the records as well. (It is not updating records in the next related table for invoices/accounts). Clearly I have set up something incorrectly - any thoughts???