Trouble to synchronize several small audio files

[olivierk <olivier.keshavjee@…>]

I'm using my PDA to record audio points, but I haven't the possibility to synchronize it with the track on the PDA itself.

When I import audio files in JOSM, I get a "Some waypoints with timestamps from before the start of the track or after the end were ommited or moved to the start."
For instance, the timestamps of my audio files are from 6pm to 7pm, but right-click > info on the GPX track tells me 8pm to 9pm.

Is it a bug from JOSM ?
If not, a tool to synchronize many audio-markers (add/remove 2 hrs on audio layer) would be great !