Weird, it was the other way roung for me earlier; email wouldn't work, username did.
I think the time is glitched. Mine keeps reverting to 67 hours, despite my playtime being around 103, and me getting the 100 hour playtime achievement. Check the achievement page, or the completion percentage, since they should be right.
Whether you want to use the data is up to you though, really. You can use it to unlock all of the jobs right from the beginning, if you want to. I'll be doing that, as well as transferring all of the special clothes items so I can use them from the start too.