Other questions

So, earlier today I attempted to restore the last backup that I had yesterday right after I had finished my last entries of the day. This backup also was missing the data that I entered yesterday. As I was fooling around with attempting to restore other pervious backups I notice that when I mounted my latest backup and clicked to "get info" about the file that the modified date and created date was august 22.  My backup was done sep 6. I then went back and looked at my last 7 backup files in the same way and they all have a modified date and creation date stamp of Aug 22 even though the dates that the back ups were actually made were  between Aug 23-Sept.  6  Shouldn't the creation and modified dates be the actual dates that I backed up the data?