Is there a way to add a condition-expr to entity-condition element of form widget that will compare two of the entities fields?

[Christian Carlow]

Does anyone know if it is possible to add conditions that compare two 
fields of an entity being searched for from a form widget using the 
entity-condition element?

In other words, is it possible to add a condition filter to OrderItems 
where the quantity and cancelQuantity are not equal from a form widget?

If not I think it should be improved to allow it.