I'm just jumping in where I saw a misunderstanding :) I think that's what they mean by unordered as that makes sense with the numbers (I think).
To some degree I agree, but there are also a lot of cases where different orders aren't distinguishable easily. "Light bright red" and "bright light red" is the best I can come up with quickly but I'm sure you get the idea.
You need 256 base words, and two substitute words, one of which substitutes for the first repeat, and the other for the second, so 258 words total.