[PatG]

I am not going to dispute your references however, your post contains 2 inaccuracies which only serve to weaken your case.

1) 81mm mortars are certainly big enough to fire a very useful smoke round - a night shoot with 81mm WP is an impressive thing - I've done it.

2) Accuracy is not necessarily a requirement for a smoke throwing weapon - you really want controlled dispersal over a fairly wide area to establish the screen. This is why the nebelwerfers were so good at it.