Can we have a flow field in a table where the calc formula refers the same table

I need to know the quantity how much is converted into order from a Blanket order. So I need to create a flow field called "TAKENTOORDER" the calc formaula is again reffering the same sales line table. 

Sum("Sales Line".Quantity WHERE (Document Type=FILTER(Order),Blanket Order No.=FIELD(Document No.),Blanket Order Line No.=FIELD(Line No.)))

My new fiedl is also in the sales line and calc formula also referring the same table.


I have tried and it is working. Is it correct or any probem is expected?


Please advice