One is putting out 5500 mcd over 90 degrees and the other is putting out 5500 mcd over 30 degrees but is rated at the same amps and a higher voltage. Seems like the total output is greater for the LED that requires a lower voltage.
Ask for a proper spec sheet. Do some research and you will find that the "superflux", "UFO", "Pirhana", etc....leds in this package are capable of handling higher current, so it's more than very likely that this transcription to the web is incorrect.
Also, these LED's are based on different compounds and have slightly different major wavelengths. To do a proper comparison, these should be the same.
Check out the
efficiency section of the LED Wiki, as that is what we are basically discussing here. While it's possible (even probable) that one LED product will have
slightly better or worse efficiency than another, especially in different wavelengths, you seem to be hoping for an order of magnitude difference that current LED technology won't support.
RandyT