Last summer I had great use of the combo FCPX and Sync 'n Link for multicams with external sound. More than often the sound- and camera-guys went out of sync time code-wise, and I could fix it by adjusting time code for start and end of clips in the modify section in FCPX. This way Sync 'n Link has no issues creating the multicam. This was in FCPX 10.2.something.
Ever since 10.3 it seems this is not a possibility anymore to adjust start and end time codes for clips, but only the creation date? Sync 'n Link does not sync by creation date. Am I doing something wrong here? Current project has 4 cams and external sound. There's no way to change the time code for each clip so t seems.