I seem to recall that using tar incremental and certain file attributes (SELinux perhaps?) simply doesn't work
What I do is touch a file, and use find to select files modified or created since the dat of that file, so something like
find /home -daystart -newer $INCREMENT -type f -print0 | xargs -0 tar --selinux -rf "$DEST"
where $INCREMENT points to a file that was touched during my last weekly backup (this is a daily incremental) and $DEST is the destination tarball. I then zip the file once created. I touch the destination initially because I'm adding to it (-r) with tar, so it needs to exist.