WinSCP has a general problem whit the time offset as regular ftp.
If I don't use time offset, the file times has an exactly difference of 1 hour, because to different timezones from my PC and the server.
But, when I use the time offset use one hour additive, then I became only 59 Minutes Offset, the server file time are exactly 59 minutes different to my local file time.
Then, I try one minute more time offset an I get two minutes. The server file time exactly 61 Minutes different to my local file time.
Did you don't understand what I mean, look at the attached pictures, you can see what I mean in one picture...