"Featherbrained Schemes" Typo?

In "Featherbrained Schemes," you are tasked with deciphering a bone fragment you find on a slain Vanu. Glidon describes it as having "Three sets of fourteen lines... two crossed out entirely, the third halfway..." He then has a breakthrough and realizes that they mean to attack the shipment of supplies, and says, "They know they come once a fortnight."

Obviously a fortnight is two weeks, but the Eorzean calendar is an eight day week. So shouldn't the markings on the Vanu bone be in groups of sixteen?

EDIT: Didn't mean to post this in general. My bad.