Back-in-time disk usage

I am using Back-in-time with encryption on a remote server (ext4 FS). I am aware that for an unencrypted backup, BiT uses hard links. Thus in nautilus, the folder size appears to be huge. The actual usage can be tracked using du from here and here. However I am not sure about the same for encrypted backups. The du seems to be growing per backup set.

My questions are:

1. Do the hard links work even for the encrypted backups? In other words, are encrypted versions of the same file under different backup sets same or different?
2. How do I find the actual disk usage per backup set? (Apart from the simple for loop: for d in $(ls -d backup_dir/*/);do du -ksh $d;done). Can this be a feature-request for BiT?

Thanks.

Edit: I am using BiT 1.1.12 on Ubuntu 18.04. The remote system is RHEL 5.1.