There's a few quirks I've noticed on the KVS timetable search where some results aren't showing through. Any ideas on what's happening?

1. Some legal connections don't seem to show up. I've come across this a few times E.g. LAD-DXB-LIS on EK, DLA-ADD-FRA on ET, MAO-PTY-POS on CM etc.
Could it be that these are all connections that significantly exceed the direct routing mileage and are therefore edited out of the results? Even if the airlines themselves publish and sell fares on these markets?

2. Some airports seem to not be available at all. DSS for instance, the new airport in Dakar yields a "the requested origin is invalid" result even if most (all?) airlines have moved operations from DKR