It's possible, too, that the pattern maker didn't want to bother writing the directions in more than one way. I've seen so many patterns where the cutting directions assume you have one sort of precut, and by the time I've drawn it and crunched all the numbers to convert to yardage, i've made the pattern. Or worse, as in the only pattern I've bought (and likely will ever buy), the explanation for yardage was so vague and dismissive, it was clear that the author didn't think it was worth her time. Although you'd think she'd want you to buy nice, big pieces instead.
hugs,
Charlotte