Sorry I read it wrong again and there is no need to crank up the fuel pressure any more with all the new injectors out there but back in the 80's when you didn't have the choices you do now it was common practice to crank the static pressure sky high to get the fuel needed. And the 42.5 would take more pressure before locking up. Hence more fuel.
And to confuse this issue what does 100% duty cycle really mean?
To me it's just a theoretic number based on a certain criteria.