Just so there's no mystery, here's why you can't download data from the AltimeterOne and AltimeterTwo: neither device actually has USB data capability.
I chose the USB plug shape for recharging because it is the single most common (and thus convenient) source of plug-in DC power, and so you wouldn't need to buy or keep track of another cable. The (+) and (-) pins of the USB plug connect to the Lithium Polymer battery charger.
It's understandable that you might see it and think: "Cool. Data!" But alas, no.
Just charging.
--John Beans, Jolly Logic