There is some inconsistency for support units.
The lighter type [Cav.] units for Support Anti-Air and Field Hospital Detachment cannot be used, but their heavier type [Car] counterparts can.
Considering that both of these units require some form of transport, shouldn't they always be unusable, like for the Anti-tank unit?

There is also some inconsistency for the Reconaissance support unit. While the basic unit can be used correctly, but type [Cav] cannot, it is unclear why type [Motorcycle] can be used?

The most logical thing to do would be to exclude any units that use any form of transport.