It really makes no sense that they should quote a 'minimum' voltage rating.At least from wikipedia there seems to be a bit of a gap in the standard for the 5 pin plugs. The yellow is for "57–75/100–130 V" and the blue is for "120–144/208–250 V AC", so there doesn't seem to be any correct plug for 100/173 .
On the basis of the (maximum) figures above, the blue would surely be suitable for 110V/173V, wouldn't it?
Kind Regards, John