Are there luns in those volumes? Because it's the SAN report, maybe it only report latencies when luns are in that volume. I still running 3.6 and I don't know this report. But when I saw your volume names, those could indicate that those volumes don't have luns.
san_ops for volumes is defined as the sum of san_read_ops, san_write_ops and san_other_ops. Can you verify if there are operations being performaned on your LUNs (using the stat CLI on the filer or using NMC) ?