For exhaust, that 265 is just about perfect, and that's what it would be... The can would be scrubbing the exhaust. They want a higher CFM for a recirc scrubber, because the air has to move twice as fast to keep the smell down inside the cab, vs. a -neg pressure exhaust fan. That's perfect!
Note... it's being used for EXHAUST in the example plan above. remember 265 out means ~265 in... yeah, it'll be a little tiny bit unbalanced, but that will create a -neg pressure enviro inside, keeping the smell in, and scrubbing the air as it is pulled out. you want the slower flow to treat the air better as it passes through the filter ((just once)) and to the outside, rather than passing through the fan several times, over and over in a recirculation scenario.