I'm running JSS version 9.96 and created a search using the advanced criteria "number of available updates" = 0, which returns 194 records. However, 194 is the total number of computers under management and it hardly seems likely that all computers are completely up to date. I did a quick manual scan and can see I have a computer at 10.12.0 so I would expect at least one hit.
Is the "number of updates" function broken?
Seth