Okay, you have filled the starting point and the ending point of the line. Iterate more and compare their areas under the curve. In the end, you should reach some graph similar to this: Warning: Spoiler! (Click to show)
Sorry, I don't understood
It should always be a wise pick choosing a fan with regard to airflow versus static restriction graphs because air flow is constant per restriction.
The airflow/striction is not a constant ratio. AP-15 is firstname.lastname@example.org H2O & Cougar is email@example.com H2O, but when all data is graphed below; at 0.04"(1.0mm) H2O Cougar is 34cfm & AP-15 is 42cfm... 8cfm more than Cougar while specs show AP-15 having less performance by 13.5 cfm & 0.2mm H20. Of course as cfm increases so does resistance which give us the real world curve. http://martinsliquidlab.org/2013/02/18/why-static-pressure-max-flow-specs-are-poor-measures-of-fan-performance/