"Adjustment is the sum of two deformations: Bolt Stretch and Part Compression" - that says everything.

Thank you for your explanation. I understand now.

So I imagine that if we do the simulation with bolt pretension in assemblies including different elements, il will be very more complex and take a lot of time to calculate the Keq, so the best solution here is to use the Pretension instead of preadjustment most of the time, isn't it ?