First of all, for synchronisation the question is not whether the files are the same, but whether one is "newer" than the other.
Thank you for the explanation. Just to inform you of one possible use of your program:
I use WinSCP for keeping a copy of my "Data Disk" on another PC. (I always sync local -> remote).
When I played around with the options (size and time), I found that on my remote volume I had a file with the same name and the same time, but with a different time. I don't know how this happened, but it did.
So I had a useless backup. And I was not aware of this, since I misunderstood the meaning of sync options.
Anyway, my workaround is to synchronize twice, with different options.
best regards, Herbert