Racelab relatives fluctuate

The relative provided by Racelab seems to fluctuate by up to a few seconds throughout a circuit. While the relative on iRacing will stay the same (within a few tenths) the Racelab overlay can fluctuate by several seconds, making it unreliable. Previously there was an option to use the iRacing relative by recently this seems to have disappeared or been moved to somewhere I can't find.