Our cars do not let off to shift because they are autos, the turbos are small and never spool down unless you physically let off the pedal. Look at a data log. Ford recirculated the BOV's to keep the car quiet. If there was a performance factor, no one would VTA their BOVs because they would be leaving performance on the table.
Manual cars on the other hand are different, unless you are no lift shifting or some other form of shifting (sequential ect) then recirc boost back into the intake tract to help the turbo spool back up is reasonable.