Apologies, it's Ctrl+T not Ctrl+M. But I'm sure you worked that out anyway.
Sorry, I thought ACDSee would do it. It does allow you to shift the timestamp, but it shifts based upon the "time of each file + constant", not "time of each file + shifting constant".
It sounds like a fairly unique requirement you have - at least, I can't imagine what you'd need it for, since timestamps are never a safe unit in Windows due to timezones and NTFS/FAT issues. I suspect you'd need a custom utility.
I could happily give you a custom build of BRU, which would utilise the existing logic but would add one hour as each file was processed. In exchange for you using the website Donation facility of course