Revel B-15 LFO setup???

This weekend I wanna try to tune my B-15 correctly once & for all...I have a couple of questions.

When setting up the sub up for levels with an 80hz crossover, the instructions in the software say to set the processor to "stereo bypass" or "surround off" with the sub off. So when setting the processor for stereo is it suppossed to be "full range" or stereo with the 80 crossover?
My next question is...What # do you enter when going thru the frequencies? Do you enter the actual measured # or do you enter + or - what the # is from the 80db level ie. for instance if the measured # is 77 do you enter 77 or -3 in the box? I hope you understand my questions.

Thanks,

Jon