hahah I had the same idea. I also cleaned and re-greased the BOV today but still have the fluttering sound at low boost.
At low boost the BOV throws the pressure back to the intake, Above 0,5 bar the BOV it blows into the atmosphere. PSSST
Don't know if the fluttering sound is bad for the turbos since APS designed the BOV like this...
Maybe a TIAL in the future ....