Can't make MAF work

A274 GM datastream description

ALDL MODE 1 MESSAGE 0 DATA LIST
Word #46
GP6EAFND GMP6-E NON-DEFAULTED AIRFLOW (MSB)
I get value 2 at idle
If I use math function GM/SEC = 512N/65536 then I get 0
I tried word#47 GP6EAFND+1 GMP6-E NON-DEFAULTED AIRFLOW (LSB)
~200 at idle and it decreases when pushing the pedal.