I actually didn't write any script. I simply set t6 as a file extension to be opened with Zorro. So when I double click the .t6 file Zorro launches automatically and displays the chart.

I've checked my process list and this is what gets executed on the double click:



From your reply I understand that the timestamps that it sees in .t6 are UTC and when displaying it converts it to my timezone which is UTC+1. That would explain the differences between chart and table. Maybe don't make any conversions by default?