Via PCV or Fuel, It wouldn't have time to "penetrate" the rings. IMO, not the same.
OTOH, I'd have to think a higher concentration of Naptha via "Motor Flush" would be "the same" as an over-night soak.
IIRC, they say you can go a few days/100 miles with light driving....Can't remember for sure. Haven't used the stuff since the 70's.