ADXL355

As much as I dislike asking foolish questions I need some help clarifying some points about this part. The way that I read the datasheet, the part reads a typical 256,000 counts per 2g +  with it set at 2g full scale. This will be the data that I will manipulate. Is that correct? Again, at 2g full scale, as I understand it, each count will give a linear 3.9 ug step per count. This gives a 1g count measurement of approximately 998,400 counts. The sensitivity of the part would then be 3.9 ug per count. Is this correct?  I guess my confusion relates to the LSB specification. 

My design work was in the days where acoustic couplers were still popular and 2400 phone line communication was still a mere twinkle in our eyes.

Thank you for your expertise.

Regards

Douglas Graham