How to add new field in Room schedule by using dynamo output

Dear all
How to add extra field to already created room schedules in Revit by using dynamo as shown in below image. For example in my building i have two rooms i.e…, Room A and Room B for my project i need to add a new filed i.e., I need to subtract room area A from Room area B i.e., (A-B)
In dynamo im getting (A-B) value, But im struck how to add these output to room schedules in Revit. Is their any node or any other package to add these field or any other method to do Please help it was very helpful for my projectAreas(A-B).dyn (13.7 KB) Room shedule