What you are missing is that the iBelink unit should already be shipping, Baikal is still shipping units, the D3 is supposed to ship at least a week before the A5, and ALL of those are going to hammer the total network hashrate on X11 coins dropping profitablilty a TON by the time the first batch of all 4 of the "large new" miners get shipped.
I won't be shocked if DASH total network hashrate is 10 TIMES the "right now" figure by early November.
With that said, as long as DASH price doesn't collapse all of these miners should have a good chance to pay themselves off, IF you get in early enough.