Look at that, they sent over one of the six that they have!
NK:
don’t worry, we have MRLS at home
MRLS at home:
it looks like you could fit entire grad packet there, i wonder why they made it so small?
Hmm…
I think the size of the opening created some challenges. Specifically the angle of firing. Around 45° is the maximum angle for the furthest distance. To hit things closer reducing the angle is needed. Clearance through the hole would be limited with a full grad stack. The firing distance options would also be highly limited. Having just the one row gives them the maximum range options.
These really seem like they are designed for single use suicide mission/terrorist style attacks. Sneak across the border looking like a regular truck. Destroy a critical target then attempt to escape.