Biometric confirmation letter which states that your biometrics was received in so & so date
if you are referring to Biometric Validation Letter (BVL) or Correspondence letter. It gets updated half way through the processing of any application ( i have seen it even takes 3 months for applns submitted from India), in fact mostly they take final decision the same day they send the correspondence letter. Moreover, their website clearly says ' starts the day we receive your complete application'. So, wondering where the confusion is...