I only use older (6.0b) Intouch, so YMMV. What time zone is the PC set up for? If it doesn't match Intouch, trends can shift around.
Usually is just one hour due to DST ("Summertime" in UK). There is some info about the TZ environment variable in the Intouch user manual, in the Hist Trend chapter. For example use <set TZ=GMT-2> in the environment variables in Windows.
Or, as a real kluge, you can edit the update time script in the histrend page using: HTUpdateToCurrentTime - 2 (I forget the syntax)