for SMBus can i just use PBP2.x I2CWRITE and I2CREAD commands w/ impunity ?

from the little i have read it would seem so ...

also what is the difference between SMBus and SBS from the perspective of getting a 'fuel' gauge or 'gas' gauge reading into a PIC ?
seems to be about the same thing maybe ?

the chips on the table are
BQ34z100 (which clearly and literally describes 'i2c')
and
BQ20z70 (which calls out SBS)
plans were laid to use the 34z and now they want to change to the 20z in the pack and it has me worried a bit
thanks in advance for any advice or experience in this area