Pretress clarification

Dear support service,

Can you provided me some clarification on the prestress load tool.

My model look at stabilizing an embankment with two row of sheet piles walls connected together by the mean of solid bar.

To simulate the connecting bar in soilworks, I am using a truss object, pre-constrain at 100kN.

I am troubled by the computation result/display.

Without prestress, the truss display axial forces between 286 - 391 kN while with prestress it seems to overwrite the computation and only display the constant prestress value, 100 kN.

I would expect the computation with active prestress to display a reduced axial range in the of 186-291 kN.

Am I misdoing something or misunderstanding something? Could you clarify it for me.

Best regards