[Orgmode] Formulas in columnview table

[Flávio]

I am using columnview table now to get some summaries of worked hours and
quantity balance as well. This is one example showing a quantity of quoted
computers and the real sold quantity:

|   | ITEM                    | Quotation | Sold | 
|---+-------------------------+-----------+------+
|   | ** Computers            |      10   |  7   |
|---+-------------------------+-----------+------+

Is there any way to automatically insert a fórmula in a third column? For
example, I could insert a "Difference" column and make Sold - Quotation and get
this result:

|   | ITEM                    | Quotation | Sold | Difference |
|---+-------------------------+-----------+------+------------|
|   | ** Computers            |      10   |  7   |     -3     |
|---+-------------------------+-----------+------+------------|

So I could change the column defintion from:
:COLUMNS:  %50ITEM %10Quoted(Quotation){+} %10Sold(Sold){+}


To:
 
:COLUMNS:  %50ITEM %10Quoted(Quotation){+} %10Sold(Sold){+}
%10Sold-Quoted(Difference)
 
Maybe I am going too far with tables and columns view and the  developers did
not intend this kind of feature because of complexity. 
But I think this would be a great feature.

Regards,

Flávio