Don't know how many of ya'll have gone to the Italian xbow site, but it's a wealth of info and various tests, run by a guy called Matthias 72 on Excal forum. this guy eats, breathes, and sleeps xbows, lol. Here's a copy of what he has to say taken from Excal forum:

On theory the comsumption increase with a square law:
for example: Phoenix comsumption factor is 175*175=30625; Exocet200 is 40000 and Exomax is 50625. In easy words that means:
Exomax eats the serving 60% more than a Phoenix or 26% more than an Exocet200.
And the consumption reason is principally due for the pression with the relase hooks. The only real way to decrease consumption is to decrease the pressure for square unit. How? Using a serving with a great size. Or a string with bigger size. If in future Bill will project a new relase hook a little bit bigger than actual(for example two times the actual surface) it will be a very good emprouvement because it will reduce for half the pressure for square unit and our serving will eat much more less.