Holding Value for a Recalc Measure

Hi,

I have a question regarding holding values for a recalc measure  Gross Sales %.

The rule is like

Rule 1

Gross Sales U = Gross Demand U * Gross Sales %

Gross Sales % = Gross Sales U/ Gross Demand U

Here Gross Demand U gets fed from a file. And business enters Gross Sales %, in turn triggering the calculation of Gross Sales U. Or if Business changes the value for Gross Demand U, the Gross Sales % gets recalculated.

However now the business wants to enter Gross Sales % first, even before the plan for Gross Demand U. They want to hold the value of Gross Sales % (whatever they have entered), even if Gross Demand U is zero.