BLM is block learn muliplier and yes is 128 at stoich which is 14.7 however with variences in gas mixtures some ppl set stoich to 14.58 at times to help offset the addatives the oil companies run so you dont run to lean and hurt motor. now to answer yoru question if the value is > then 128 it is then leaner then stoich. the value is raised cause the PCM is trying to correct for fueling. if the value is < 128 then the vehicle is rich and the pcm is trying to correct it back
matt if youre trying to tackle this yourself and in over your head some. ill be more then willing to help you dial this car in. you know how to contact me