II12yanII

So if im reading that right. It's just reporting the incorrect space. But its usable space is what it more should be?

Im new to unraid. Started my new server last week. Im on unraid 7.2.4 i created my first pool with 4 16tb drives with zfs and raidz2. So I have 30 tb of storage. As I transfered the files from my old raid. I got that raid low enough I could move a 16tb drive from that to the new pool. Once unraid did everything it needed to do to add the drive to the pool. I now only have 38 tb of usable storage. I should have around 42-43 tb of usable space with 5 16tb drives right? My storage capacity only went up half of the new drives size. I know there's overhead and what not with raid. But 38 tb seems low to me. Or am I just dumb. As soon as the drive finished the balancing it went right into scrubbing. Not sure if that cause the problem or what.