Does appliance wattage differ by country, since the voltage does?
First, it will only "use" what the load demands.  Second, you don't know where it's limitation is.  If the true limitation is its input current, then yes, you get less power at a lower input voltage.  However, the maximum power it can put out may very well be limited by something else.  In that case, it will only put out up to that maximum power before it will either shut down, drop the output voltage, violate the input current spec, or catch fire.

Look more carefully at the nameplate.  It probably says something about its output voltage and current.  That is what you can rely on as long as you give it input voltage within its specified range, which in this case seems to be to simply plug it in anywhere in the world.