Data columns in BPS layout

Hi,

My current BPS layout has three columns, they are cost,price and margin respectively. The user now ask to add another column call "alert" after the margin column.

The logic is that if the margin is less than 10%, then the alert column should marked with "X", otherwise leave it blank.

In order to add a column after margin column, the added column have to be key figure which will not allowed characteristics,while all the other key figure type such as amount, quantity, date ect will not take

"X".

Any idea or suggestion.