Mr. Peter
Thank you for the detailed explanation.

I now understand how adjustment is calculated.

How ever if the adjustment is calculated like this(only considering the deformation of the bolt without considering the deformation of the clamped object) , is this the reason why there is larger discrepancy between the adjustment value and real displacement when there is clamped object?
If so, in a real world case if we use the adjustment value to apply the bolt force we would have a higher force than the rated force right?