Right now I am reading related passages/sections from ICAO Annex 10 Volume 4 and Technical provisions for Mode S Extended squitter.
Airborne position squitters are randomly distributed in between 0.4 and 0.6 seconds. Even if we update Airborne Position Register 05 with utc-synced estimated position, transponder's choice of transmit time might cause in shifting into next epoch(basicly 0.2 second lag).
Increasing rate of update(5hz suggested for now) might only reduce the problem.

Are ADS-B Airborne position squitters inherently inaccurate?