Usage of ‘at least’

Today I received an email from Skype, letting me know thus:

“Notice that Xbox now requires that you sign in at least every 5 years to keep your gamertag active”

This strikes me as odd, as a native speaker. To say to sign in ‘at least every five years’ would imply that it be a requirement to sign in every five years or greater, would it not? Does the above sentence somehow mean the opposite if what it means literally?

Thanks.

Edit: I just came to think that perhaps they had meant to say ‘at least once every five years’, but what they have written then seems like a mistake to me instead.