This is how McKenzie did last year with his top half of the 1st round:
1. Celebrini (#1)
2. Demidov (#5)
3. Levshunov (#2)
4. Silayev (#10)
5. Lidstrom (#4)
6. Dickinson (#11)
7. Buium (#12)
8. Parekh (#9)
9. Helenius (#14)
10. Iginla (#6)
11. Sennecke (#3)
12. Catton (#8)
13. Yakemchuk (#7)
14. Eiserman (#20)
15. Connelly (#19)
McKenzie almost nailed the top-15 in the draft, he went 13/15 with missing out on Brandsegg-Nygard (#17, went #15)) and Luchanko (#19, went #13). And at that point, I think it's even cherrypicking to say he was "wrong" there. The prospects at that level are mostly the same caliber.
But that said, he only went 4/8 with the guys who went in the top-8, where guys ranked #10, #11, #12 and #13 finished in the top-8 while guys ranked #4, #6, #7 and #8 didn't finish in the top-8. Even with McKenzie having almost as good of a draft projection as you can get, he still only went 50% in the top-8.
That's why I think it's needless to worry about whether their pick is #8 and if they'll miss out on the top-8. Most likely, 2-4 guys in the top-8 will slide to the 9-14 range while 2-4 guys in the 9-14 range will jump into the top-8. And it's entirely possible Dubas is one of the guys that is doing that.