You are correct in saying that those pseudo transport streams are for the legacy VOD system. They are dynamic, so streams only appear in them when someone in the local area is actually watching on demand content. The local area is more the local neighbourhood for these streams, not the entire region as would be the case for transport streams 1-34 or 101-102. If nobody in the local neighbourhood is watching on demand content at the time of the scan, nothing will show up. The scan would probably register signal strength / quality data but that's about it, and DBR doesn't track that data.
I note that the latest DBR scans are showing data for a couple of these pseudo transport streams, which indicates that someone in the neighbourhood local to the DBR scan site was viewing VOD content at the time of those scans.
It's worth noting that scan data for these is hyper-local and distribution is more closely related to DOCSIS than to regular DVB-C. These streams don't show up at all on SI data scans.