The depower/trim system is tensioned with 60kg in the factory to set all splices and connections in these thick strong lines.
Flying lines are added after this procedure and the bar is calibrated with 5kg load on each line.
Depending on your weight and usage, the load on the depower/trimline system may exceed the 60kg applied in manufacturing
and hence, after one or two sessions that part of the bar may stretch an additional few cm.
You can correct this increased length in the depower/trim system by shortening the trimline as shown in below pdf.

Bar calibration