Yes, that appears to be the answer. Pretty new to this, but ended up with the following code, which appears to do what I want. Added a Boolean checkbox for the report:
CALCFIELDS(Quantity,"Qty in Pick Zone","Qty on Sales Order");
IF TopPriority = TRUE
THEN BEGIN
IF "Qty in Pick Zone" < "Qty on Sales Order" - QtyFilterbyCust THEN
Replenishmt.Replenish("Bin Content",QtyFilterbyCust);
END
ELSE BEGIN
IF "Qty in Pick Zone" < "Min. Qty." + "Qty on Sales Order" - QtyFilterbyCust THEN
Replenishmt.Replenish("Bin Content",QtyFilterbyCust);
END;