Yes, this works. Still a little clunky. The If command has more arguments, and you still need another step.
With that, I'm finding arrays containing 16+, 15+ and 12+... at a rate of 29%. It occurs to me that 17+, 14+, 12+... can also give us a +8 AC at level 4, so add some %age more for that. (Any quick estimate how much?) A party of 4 is therefore more than 75% likely to contain one on their first set of characters. Which explains what I've seen at the table.
Our
TotYP group (4 characters) included one character qualifying with 17, 14, 12, 12, 11, 11 another with 18, 15, 13, 12, 10, 8 and a third with 17, 17, 15, 13, 13, 9. It was that third character that took BS: they'll have +9 AC at level 4.
Our
OOTA group (6 characters + 5 replacements) included six qualifying characters (I have their rolled arrays, if of interest). The worst qualifying array from that group is perhaps this one 17, 16, 14, 9, 9, 6 which can be set up for +9 AC at level 4, but has some low scores to work around. Could go 6, 19, 14, 17, 9, 9 which gives it a couple of low saves partly compensated for by the Wizard class. So far, I have found that the way 5th edition is structured makes having a few low scores not particularly punitive.
My experience has been that an array enabling a +8 or +9 AC at level 4 has been the norm not the exception on a per party basis: usually more than one. What sort of arrays has your group seen? Any qualifying?