Are backups broken?

Ive used zima for 1.5, 1.5 beta 1,2,3 and 1.6
and all versions dont really do backups correctly.

I am backing up another NAS to my Zima storage, and I have to restart the backups manually even though auto is on. Also the backup starts from 0 files even though I already backup up all previously. This puts unnecessary wear on my disks.

Any insight would be appreciated