Prescribed Displacement & Reaction Forces

Hello 

I am currently performing a linear simulation, where i know the allowable displacement for which i require to find the force required for that face to deform. I used prescribed displacement fixture and fixed support Boundary condition as below.

I ran simulation with the above set up and used Result Forces option under Result Folder. Used the fixed surfaces to find the reaction forces.

To confirm this, i worked the other way by using the reaction force as input (from the displacement study ) to find out the displacement which is obtained. But unfortunately the results doesn't tally up.

Can anyone help to give some comments to perform this simulation please.

SolidworksSimulation