I've recently been involved in a discussion over different interpretations of the following sentence (paraphrased):
Users may update their information every two weeks, at maximum.
The intended meaning is "no more frequently than once every two weeks", but some people seem to read it as exactly the opposite ("no less frequently"). A quick search on Google threw up examples of both interpretations (albeit usually sans comma), so now I'm somewhat stumped.
To my mind, "every two weeks" specifies the frequency at which something may occur, while "at maximum" indicates that this is the highest frequency, not he largest interval of occurrences.
Is there any one "correct" interpretation of this sentence, or is the wording simply too ambiguous?